August 22, 2017


Going the distance...

We talk a lot about establishing more natural-functioning/appearing systems, and many of the nuances associated with getting them up and running. And of course, we talk about how to manage these systems for the longer term. However, we seem to spend a relatively small amount of time talking about what happens in these tanks over the very long term, right? 

So, I thought I'd touch on some of the things I've noticed in our blackwater, botanical-style tanks over the long term, and how maintenance affects their function and overall health.

First off, there are some characteristics of these types of tanks which require a fair amount of continued management that keep them functioning as blackwater tanks; most notably, the continuous addition of more botanical items to replace those which break down, be they leaves, wood, or seed pods and the like- in order to maintain not only the visual "tint", but the beneficial humic substances and other organics contained in these materials. 

Over time, many of these compounds are dissolved into the water column, and these botanical materials will no doubt lose some of their efficacy as "environmental enhancers."

And obviously, this sort of "active management" not only creates a more stable environment for your fishes, it provides an opportunity to continuously engage with your aquatic environment on a very regular basis. This process is one of the most important aspects of managing any aquarium, but is especially critical in an environment in which the very structure of the aquascape itself evolves and changes over time!

Now, unlike other tanks I've managed over the years, such as reef aquariums, planted tanks, etc., where you need to sort of change or evolve your husbandry tasks as the tank ages (i.e.; pruning, revising fertilization schemes, etc.), the botanical-style blackwater aquarium seems to benefit from the same types of maintenance tasks throughout its functional lifetime. Some hobbyists choose to let their botanical items remain in the system until fully decomposed; others prefer to remove items just as soon as they lose the "pristine show look." Regardless of how you handle the "botanical breakdown", you're more-or-less following the same practices over a long term. 


And of course, water exchanges are as important a part of the management of our systems as any other. The dissolution of organics and "reset" that water exchanges provide are one of the "cornerstone" practices in aquarium husbandry, and will help continuously hold your environmental parameters. 

As any aquarium ages, it's essential to at least have a handle on what is happening chemically. In the botanical-style, blackwater aquarium, it's nice to conduct basic water parameter tests early on in the tank's existence, to establish a reference "baseline" of the tanks typical "operating parameters".  In a typical tank, you often see a gradual reduction in pH over time.  This may be caused by acids forming from accumulated nitrate and other nitrogenous compounds and over time, as they overwhelm the buffering capacity of the tank. This seems to be much more common in higher pH systems, such as African cichlid tanks, reef aquaria, etc.

You will likely find, as I have, that with the consistent management of your blackwater tank, very little in the way of "parameter shift" appears to occur. I've seldom noticed any sort of appreciable pH decline over time in these tanks (probably because you're starting out with lower pH!), and nitrate and/or phosphate levels tend not to vary significantly at all with consistent botanical replacements and water exchanges.

I tend to monitor TDS a lot in botanical tanks, and I've found that I will see a "range" of 2-3 ppm at the most, in which the parameters seem to stay throughout the lifetime of the tank. Any deviation from this should be something that you should investigate. Not necessarily a "bad" thing, as TDS can be just about anything...yet it does function as a sort of "yardstick" for environmental consistency.

One physical maintenance task that I have found to be continuous and necessary is the cleaning of filter intakes, mechanical filter media, and water pumps. With a constantly-decomposing array of botanical materials streaming into the water column, lots of small debris tend to get sucked into filter intakes, pumps, and of course, mechanical filter media. These need to be cleaned/replaced on a regular basis; perhaps even more frequently than other maintenance tasks. It's simply part of the game when working with a botanical-style blackwater aquarium!

Nothing we've mentioned here is earth-shattering or revolutionary, from an aquarium husbandry standpoint. However, seeing that for many hobbyists, this is their first experience at managing a botanical-style blackwater aquarium, I think it's not a bad idea to review this sort of stuff. Seldom are big moves or corrections required. Rather, it's really a combination of little things, done consistently over time, which will see your aquarium thrive in the long run. 

Stay consistent. Stay active. Stay observant. Stay involved.

And Stay Wet.


Scott Fellman

Tannin Aquatics 

August 21, 2017


It's okay NOT to tint...

We've talked about the idea of "clear water" botanical-style aquariums before. In other words, aquariums in which botanical items are utilized, where the water remains clear, not amber-to-brown-colored, but it is something that we as a group tend to look the other way on, which I think is funny. I mean, a few years ago, you were considered sort of odd by the aquarium world for wanting brown water. Now, in our community, NOT wanting brown water is often looked on a bit strangely, lol.

On the other hand, it is absolutely possible (and entirely realistic) to have an aquarium with botanical materials that does not have the lovely "cafe au lait" look that we all know and love so well!

In a twist on one of our own marketing slogans, "It's okay NOT to tint..."


Although the three "classical water types" (white, black and clear) are used by science to describe many of these habitats, aquarists tend to classify water as "blackwater" or "clearwater", which, although not scientifically "pure", tends to make our understanding and discussions easier!

And the reality is that there are many, many habitats throughout the world which have tons (literally) of botanical materials in them, yet have relatively clear water. It's certainly not a given that the presence of leaves, wood, and other botanical materials in a given body of water will result in brown water and low pH. Rivers like the Juruá, Japurá, Purus, and Madeira) are turbid, with water transparency that varies, and they transport large amounts of nutrient-rich sediments from The Andes. Their waters have near- neutral pH and relatively high concentrations of dissolved solids.

The Rio Xingu and Tapajós are classic examples of "clearwater" rivers. One of the largest tributaries of the Amazon, the "Xingu" has an abundance of rock, and a higher content of dissolved minerals than a blackwater habitat like the Rio Negro. There is not much suspended matter because the rock formations which the river courses through are ancient and no longer erode in the current. The pH varies between 6 and 7.

As we've mentioned many times, water color, although helpful to us aquarists in some respects, is not an absolutely reliable indicator of the pH or ionic composition of the water! There is no substitute for good, old-fashioned water testing!

Interestingly (and perhaps, confusingly) the lower section of some Amazonian black-water rivers such as the Rio Negro, Tefé, Uatumã and Urubu in Brazil; Nanay in Peru and some streams in Colombia can have ionic composition and/or pH-values similar to the white water rivers, and not like the typical Amazonian blackwater rivers. It is though by researchers that low electrical conductivity values can be responsible for this phenomenon. 

In addition, it's though that many rivers and streams have to be considered as “mixed waters” resulting from the influence of tributaries with different physical and chemical properties of their waters.

As if we don't need more confusion, right? Talk about "muddy waters!"

So, for us aquarists, the arguments and discussions can rage on and on and on, and aquarists who have been to various parts of these rivers may observe somewhat different characteristics than others...and be 100% accurate in their findings! Generalizations, although often a "no- no", may actually be useful to us. (gulp)

The implications of all of this stuff are that, if you're looking to accurately recreate the water conditions from which the specific fishes you keep come from, you would be well-served to determine, as accurately as possible, where they originated from. With wild-collected stock this might be easier (assuming the collectors/distributors possess and make this information known (Hear that guys? A good idea!) to hobbyists, the ultimate "end users" of their "product' (that sounds awful, calling fishes "product", but I think you get the point...)

How do we achieve "clear", "botanically-enhanced" water? Well, of course, you can start of with water with minimal dissolved solids (RO/DI) and you can prepare botanicals and use them as you see fit to accurately represent the topography of your subject body of water. However, you'd likely use significant applications of chemical media, such as activated carbon, to remove the "tint." And of course, buffering substrates or rocks as needed, in more neutral situations.

We know from experience that some botanicals are less likely to impart significant visual tint to the water, simply because of their composition. The "harder" materials, like "Jungle Pods", "Save Pods", "Heart Pods", etc., although perfectly capable of leaching some tannins into the water, seem to impart significantly less color than materials  like leaves, or softer, more fibrous botanicals like "Rio Fruta", "Ceu Fruta", "Coco Curls", etc.

Now, there are numerous approaches to preparing water for our aquariums, and many, many different viewpoints and ideas among hobbyists as the "best" way to do things. However, at the end of the day, we all need to operate in a manner which we can understand, consistently replicate, and are comfortable with. And so much of this comes with education, discussion, and sharing of ideas. 

This brief, highly-generalized discussion was not intended to be the last word on this topic. Merely a brief introduction of some "talking points" that we as hobbyists can use for further research and discussion for this interesting and most important topic.

There is so much to learn, and even more to experiment with in the context of our botanical-style aquariums! 

Stay curious. Stay creative. Stay thoughtful. Stay open-minded.

And Stay Wet.


Scott Fellman

Tannin Aquatics 

August 20, 2017


The botanical buffet...

If you follow this blog over the past few years, you've probably noticed that we cover pretty much every aspect of the use of botanicals in our aquariums...Like, probably more than anyone ever has or cared too, lol. However, once as aspect of botanicals that we haven't really given much attention to is discussing them in the context of food.

Yup, eating them! Or, perhaps more specifically, serving some substenance either from them directly, or from the living materials they recruit while underwater.

It's long been known that many species of fishes, particularly Panaque/Panaqolus and some Hypostomus/Cochliodon love the stuff. These species are equipped with teeth specifically 'designed' to gouge wood. And there's probably another odd one or two that consume it as well. Now, you should be aware that wood 'eaters' don't eat the wood per se, they consume it as by product of their overall feeding strategy.

(The "business end" of Panaque nigrolineatus by Neale Monks, used under CC BY-SA 3.0)

In fact, some recent scientific studies have corroborated digestive enzyme activity profiles and gastrointestinal fermentation levels in the fishes’ GI tracts, suggesting that the "wood-eating catfishes" are not true xylivores such as beavers and termites, but rather, are detritivores like so many other fishes from the family Loricariidae.

In fact, the conclusion of one study indicated that "..the fishes’ whole digestive strategy ranging from intake, to passage rate, digestive enzyme activities, gastrointestinal fermentation, and decreasing surface area in the distal intestine suggests that these fishes are geared for the digestion and assimilation of soluble components of their detrital diet. However, the wood-eating catfishes do take macroscopic detritus (i.e., woody debris) and reduce it to <1 mm in diameter, which likely has significant consequences for carbon cycling in their environment. Given that much of the Amazonian basin is unstudied, and much of it is under threat of deforestation (leading to more wood in waterways), the wood-eating catfishes may play a crucial role in the dynamics of the Amazonian ecosystem, and certainly in the reduction of coarse woody debris."

(German DP. Inside the guts of wood-eating catfishes: can they digest wood? Journal of Comparative Physiology B, Biochemical, Systemic, and Environmental Physiology. 2009;179(8):1011-1023. doi:10.1007/s00360-009-0381-1.)

Interesting, right?

And it has some implication for how we keep these fishes in our botanical-style aquariums, right? I mean, we have no shortage of pics of your Plecos tearing into various botanicals, ranging from leaves to seed pods, like the "Teardrop Pods", "Savu Pods", etc. So, based on the study above, it would suggest that at least part of the pods do form a part of the diet of these fishes, and in the process of consuming them, the fishes are helping enrich the aquarium habitat. 

Now, the botanicals themselves may not be "the whole meal" for many fishes, but the biofilms, algal threads, and other biocover which grow on them do provide foraging for many fishes. A number of us have noticed a wide-ranging variety of fishes, from Barbs to characin to cichlids, feeding actively on the materials on the materials which are "recruited" by submerged botanicals.

This type of activity has led me to postulate that the use of botanicals can perform a definite "feeding support function" for a wide variety of fishes. 

further, I have this hunch that it might be an interesting experiment to utilize botanicals as part of a more "natural" fry rearing system for a number of different types of fishes. The fact that they seem to "actively recruit" biocover and microfauna as they break down indicates to me that they might be a nice way to provide some supplemental natural foraging for fry. Now, I'd be cautious about utilizing large number of botanicals in unfiltered or minimally-filtered rearing containers, as the possibility of the CO2 levels rising (or conversely, oxygen levels being depleted) as the botanicals break down en masse exists.

Rather, I see utilizing a "field" of botanicals in a more established, well-filtered natural system, containing a fine, shallow bed of sand or other substrate; perhaps even some floating plants as well. Based on some of the observations I've made, as well as some of yours- of fry foraging and seemingly actively feeding off of the life forms in the botanicals- I think this could be a legitimate and very efficient way to supplement the feeding of a variety of fish fry, particularly those which would benefit from a continuous source of food.

And of course, there's shrimp.

I almost don't need to touch on what has been known for decades- that many of the ornamental shrimp hobbyists know and love tend to consume leaves and other botanical items. Again, it's probably a function of them utilizing materials attached to or contained within the structures of the botanicals, but they seem to do a great job at breaking down botanicals in our aquariums, don't they?

I feel that one of the most incredible benefits of utilizing natural materials in our aquariums is that they truly bring out the natural behaviors of our fishes- whether it's rasping at a piece of driftwood, eating biofilms off of the surfaces of a few seed pods, sheltering in plants, or sifting through a field of decomposing cattapa leaves for crustaceans. Even if the foraging activities yield relatively minimal nutritional benefit for our "wood eating" (or more appropriately, "wood-processing) fishes and fry, I think just having some of these materials available to perform their natural functions is invaluable to them.

And functional 'scaping is a large part of what we're all about, isn't it?

Stay creative. Stay thoughtful. Stay focused. Stay excited.

And Stay Wet.


Scott Fellman

Tannin Aquatics 

August 19, 2017

1 comment

The Very Greatest One...A "Luft" Story

Greatness comes in many packages, many forms. In sports, boxer Mohammed Ali earned the title, "The Greatest" from sports fans worldwide. The three-time World Heavyweight Champion easily earned his nickname. In the aquarium hobby, it’s tough to earn the rating of “good”, let alone, “great”. However, I think that I own a product that has safely earned the title of “The Very Greatest One”.


The year was 1981, and this teenage fish geek needed to make what was then a major purchase for my hobby- a strong, reliable air pump to power my Necktonics undergravel filter in my 20 gallon marine tank, complete with two Blue Damselfish, a Percula Clown, and an H. crispa anemone, which “thrived” under my DIY triple Vita Lite fluorescent fixture. (Actually, I think it did thrive- had it for over 7 years before I gave it to a friend.). I was sick of unreliable, cheap pumps, so in scanning my well-worn copies of FAMA magazine, I saw an ad for mail order firm Aqua Engineers (Remember them? They were the “Live Aquaria ” of their day.No "Prime" shipping, either, lol).  They had a lot of air pumps-but they also had THE pump. The one every fish geek at the time loved.

After much research, and a lot of saving, I decided to make a big investment (I think it was like $19.95) in a Tetra “Luft” pump. This was a huge move for the time- the Luft was the Ecotech Marien Vortech of its day, the European high-tech answer to the American “Silent Giant” air pump (remember that one?).  The little brown Teutonic wunderkind delivered large quantities of air in near silence- a huge plus when your aquarium was in your bedroom! With a simple twist of a rheostat, the mighty Luft could be cranked up to deliver precise volumes of air effortlessly up to 7 psi. I had the “Porsche of air pumps”- and I was still in high school!




The little German workhorse powered tank after tank, delivering air to everything from my killifish breeding setup to brine shrimp hatcheries, even going to work on my quarantine tank (thanks to fancy air management with sexy plastic gang valves). 

And yes- I had a QT even back then!

The dawn of MTV, “Reaganomics”, New Wave, college, the fall of the Berlin Wall, The Gulf War, the “Grunge” movement, the “” boom and bust, two major earthquakes, several relationships, 4 different houses, the new millennium, 9/11, 6 U.S. Presidents, and literally thousands upon thousands of hours of operation. My little brown Luft has seen all of these things, faithfully and silently cranking out air.

Right now, it’s doing duty once again on a quarantine setup. For 5 years prior, it was working on a small tank full of Hawaiian Red Volcano Shrimp (Halocardina rubra).

A workhorse!

 In fact, this small wonder has worked continuously in one capacity or another for 34 years, a longevity/reliability record few products in any industry could match! Short of rinsing the little air filter that slips on to the bottom of the pump every so many years (or when I remember to do it), I have not had to do any maintenance.

Unfortunately, the pump is no longer marketed under the Tetra name, but the design has apparently been repackaged by Coralife-but it’s still called the “Luft” pump- still brown, and still amazing. It operates under a wide variety of conditions, and represents-to me- the pinnacle of air pump design and engineering.  I swear, this thing will outlive me. Talk about value for the dollar!  It’s been worth every cent- although the price tag, when I Iast checked- was a dizzying  $52.99!

Greatness has always come at a price, I suppose.  

And then again, I haven’t had to purchase an air pump for 36 years, so what do I know?

We all have our favorite product, be it a protein skimmer, high-tech powerhead, light bulb, etc. Mine is just a humble air pump.  Well, not just an air pump. It’s a noble and reliable little device that has powered my aquatic hopes and dreams for over three decades. A family heirloom. It’s not just a piece of aquarium equipment- it’s a part of my family! Live long and prosper, my little brown friend.

To me, you are truly The VERY Greatest one!

Till next time….


Stay devoted. Stay passionate. Stay Undefeated!

And Stay wet.

Scott Fellman

Tannin Aquatics

August 18, 2017


Coming home. Again. For good.

I was talking recently with a friend- fellow aquatics industry vendor- who was lamenting about how "burned out" he was; how "disconnected" he felt from the hobby...He was very "numb" to the whole wonder of being a fish geek. He had been sort of "going through the motions", and that was about it. And it was affecting both him and his business. It was obvious.

We had a little discussion about his "burnout", and it made me pause and reflect on my own experience with this same phenomenon from not too many years back...

A little background:

Okay, so most of you know by now that I'm actually rather well-known in the reef aquarium world...Oh, that sounded a bit arrogant, huh?

Wasn't the intention, trust me. My point is, I'm not all that well-known as a freshwater writer or "personality", if you will. However, in the marine aquarium world, My name is well known, and I've been pretty hard to miss over the past decade or so. I was everywhere. Spoken at tons of conferences, authored a lot of stuff, etc. I have traveled around the nation and the world on a monthly basis, speaking to clubs and conferences. I was a co-owner of Unique Corals, which became one of the reef world's most respected livestock vendors/coral propagators. 

I'm a lifetime fish geek.

However, until a few years ago, I was very peripherally involved in the aquarium hobby on a personal level...It had been a few years, and that was too many. Oh sure, I kept tanks and stuff- our facility at UC was like 18,000 gallons of saltwater! And over that time span, I tested every product we offer at Tannin in my own freshwater tanks...But the sad reality is that I felt "disconnected" from the actual hobby, until quite recently. Everything was "business."

Fortunately, a couple of good friends noticed this, and literally coerced me into getting back into the game on a personal level...and I've never been happier, aquatically! All it took was just setting up some tanks for ME. Who would have thought it would take the "intervention" of friends to make me enjoy the hobby again? But it did. And I won't question it, either!

It's applicable, of course, to ANY aquatic field of endeavor within the hobby. This is a story of a personal journey... almost "confessional" in a way, and was a very therapeutic piece to write! 

I digress again...



A few years back, I made a (for me) the wonderful and long-overdue transition back from “clinical” aquarist to “practicing” aquarist once again, and it’s felt incredible.

Let me explain...

I found myself slipping into the role of what I call “clinical” aquarist.

What do I mean by “clinical?” Well, there are a lot of people in my position, like, way more than you'd imagine- owning and building hobby-related businesses, perhaps writing, speaking, and “living the fish geek life” like I do, who don’t have a tank that they maintain everyday strictly for pleasure; who perhaps ply their stock in trade in the aquarium world for years without maintaining an active personal aquarium. Yes, they’re in touch with the hobby, and the animals, and the gear…but they’re not in “the final few inches” of what is really happening.


I’m not saying that this is bad. I'm not saying that having a personal tank is a mandatory prerequisite for success or anything.  I’m just identifying what was a problem for me- and a few other people I know.

Where it can get bad is when you find yourself regurgitating stuff from a long time ago- that is perhaps woefully outdated- when rendering advice to others; or perhaps you are staying current on the latest and greatest and "preaching" it without actually practicing it…THAT is a sin in the aquarium world, IMHO. There’s lots of that percolating around the hobby, more than you'd think-and it's obvious especially when you find yourself “in the know”, speaking and traveling around hobby-related conferences and events. 

Then, there is an even smaller fraction of people (thankfully), who spend much time criticizing others in the hobby and industry, slinging negative publicity for practices/products/people they don’t “approve” of, and generally rallying their buddies to give them a social media “pat on the back” while they spew forth their vitriol with unabashed nastiness…all while not even being a “practicing” aquarist. Angry folks.


Yeah, there are a bunch of people who are just like that, and it’s sad. It’s sad, because they don’t experience the real pleasure of actually keeping an aquarium. It’s sad because they are so myopic in their focus that they can’t get past themselves, their self-appointed grandeur, and the adulation of their small “rooting section” who heap on the “attaboys” whenever they pop up on social media discussions, etc. 

They don’t get it. At all.

It’s also sad, because some of these people are immensely intelligent, focused, and dare we say, experts about certain things, yet they can’t get beyond their negativity and disdain for others who they feel have “violated” the sanctity of “their” fields of expertise. Rather than sharing something useful, they choose to simply criticize. 

Rather than disseminating their immense knowledge in a useful and helpful way for hobbyists, they find it far easier to thrive in a sea of negativity, attempt to diminish others, and thrive off of the virtual pats on the back from their small, yet vocal groups of friends, none of who have the courage to stand up on their own and let their individual voices be heard, lest they suffer the “wrath” of their demigods.

Totally sad.  And not a place you want to go. That's a different variation on this theme of "clinical", but it's shockingly not that uncommon in the aquarium world. 


I realized not too many years ago that I was drifting into the larger, yet equally distasteful (to me) category of “clinical” aquarist, who, although I ran a coral facility and was "semi hands-on” with the animals, equipment, and practices on a daily basis, found myself without a home aquarium of any significance, and felt oddly “detached” from the “real world” of the hobby. Sure, I talked to hobbyists everyday, went to conferences, immersed myself in it all; yet, rather than relating to them in a manner based on “Yeah, I’m going though that algae bloom, too!”, I was falling back on my experiences of the past (“Yeah, I had an algae bloom back in, 2009- maybe 2007?Anyways, it sucked…”). 

It felt, well...yucky. (perfect word for it.)

And I realized the scary fact that I was becoming one of "those" people...and I didn't like it. At all.

I've spoken or presented at all of the major reef aquarium conferences...9 MACNAs, several Reefapaloozas, Reefstock, IMAC, and dozens and dozens of clubs and smaller conferences around the world. I’ve guest blogged on Reef Builders, Reef2Reef,  been published in magazines- all that stuff. Still do. My daily “rants” and blogs are syndicated and read by thousands of hobbyists around the world…I’ve been told over the years that I’m the “morning coffee”- the “cold pizza”- for a lot of fish geeks to start their days.

It was quite satisfying to a great extent. It was pretty cool (still is) to have the honor of your attention...It's an amazing connection to experience.

Yet something- I was never able to quite get a finger on what it was at the time- was missing.

That was sad. And oddly unsatisfying….I mean, all of this cool stuff, friendships, etc. and the very reason for it all was not in my life:

Being an active hobbyist on a practicing, personal level.

We built this amazing company at Unique, which dealt intimately with the art and science of the reef keeping hobby, and yet, I feel like somewhere along the way, I actually forgot how cool it is to be a real hobbyist. I don’t know if it was the personal trauma I experienced when my father passed away, or the life changes I went through, or just spending 24/7/365 hyper-focused at building up Unique Corals, and then here with Tannin Aquatics…Don’t know. But it doesn’t matter now. 

What matters is that I knew that I wanted to be myself again. A hobbyist of the geekiest type.

And that’s why I decided, as one of my friends eloquently put it, to “come home” and become a “practicing aquarist” yet again…and I’ve never enjoyed it more. It never meant more to me to come home to the sounds of an aquarium. To work about how my tanks will do when I go out of town. To deal with the weekly water changes, frozen food in the fridge....spilling on the new hardwood floors...Since my "awakening", I’ve started several new aquarium systems, and have enjoyed the process in a way I never did previously..It’s brought back the familiar, yet seemingly atrophied feelings of excitement, anticipation, engagement, responsibility, and true camaraderie that you encounter when playing with fish tanks and sharing experiences with your friends. As someone who likes to write, every day provides new topics and ideas about things to share, question, laugh at myself, discuss…After a very short time, I felt like part of the community again. 

That’s really good. 

And I feel a bit more, I don’t know- mature, perhaps? Like someone who’s lived a bit, and can take those experiences and apply them to his everyday aquarium practices. It’s super empowering. It’s not like I was “away”- but it sort of felt like I was “on the outside”, watching others enjoy this amazing thing that I could only sort of longingly stare at through the dirty window. It’s definitely made me a better industry person, too. Relating even better to my customers- my fellow fish geeks- and the people whose I address at conferences and club meetings. You people- who really matter the most.

I remember many days at Unique, when hobbyists would call or visit, giddy with excitement about receiving that cool Acropora frag or exotic new fish, and we’d talk about it…And they’d ask questions, and I’d answer them and discuss their issues, feeling just a little twinge of…I dunno- jealousy, perhaps- that they were enjoying this amazing little thing that I just sort of took for granted. And it just kind of built from there..the need to "get back over the fence. "

I actually feel like apologizing a bit for not feeling it for too long.

Working daily with some incredible guys at Unique Corals, who practice geeked-out reef keeping at its highest level- just kept the fire burning. One of my friends must have just known- sensed it…He would always pull me away from my desk to check out this or that coral, light, crazy project he was working on…or to cut frags, help move some corals- whatever- just to get me away from the darned computer and get my hands wet.  Another would urge me to “go fishing” at the wholesalers her in Los Angeles with just geek out on the cool fishes and corals. Little "interventions", to pull me away from the spreadsheets and order forms and such, if you will.

And it worked. It was like waking up out of a coma…

I learned that you CAN come home again- I learned that sometimes, you have this wonderful thing right in front of your eyes- and you just need to appreciate and enjoy it for what it is…this hobby, this culture- this WORLD that we have is amazing, precious…and beautiful. I would walk my coral grow-out raceways gawking at the corals, thinking exactly what other hobbyists who visited our facility thought: “Man, I’d love to see that Acro in MY tank!”


That was a few years back...and I haven't ever went back to that lonely place again. Never will.

Now, when I'm putting together one of your orders, or perhaps helping a new "Tinter" decide on which botanicals to choose for his wild Gourami tank, I feel the sense of excitement, of envy, and camaraderie- and I gaze across the office to one of my tanks...and it's like, "Yeah, I'm right there with you!" And I think it's enabled us to build an amazing business here at Tannin Aquatics. A business built on the emotions and passions that you can only relate to if you're a genuine, 110%-enaged, fully-committed, practicing aquarium hobbyist!

Why am I sharing this personal journey with you? Well, perhaps it’s a bit therapeutic for me…Perhaps it’s a good lesson for those of you who might have "pulled away" from the hobby a bit and feel like you're missing something. Perhaps it’s simply a public affirmation for me about the fact that it's not impossible to come back- and I proclamation about never wanting to stray from the path again. I offer this to you as less of an explanation of MY hobby journey, and as more of a “life raft” to those of you that, for whatever reason, feel like you’ve strayed away from the hobby that you love so much.

Oh, and my friend? He just set up a 125-gallon Amazonian biotope tank. It's killer.

He's back.

If you’re out there, drifting in the current. Just know that it’s never too late to climb back aboard. 

And never more satisfying than now.

Stay involved. Stay committed. Stay in contact. Stay excited.

And Stay Wet.


Scott Fellman

Tannin Aquatics

August 17, 2017


It happens in the "mangal"

With interest starting to increase in the brackish-water, botanical-style aquarium, we're seeing a lot more questions about the habitats and ecological niches where our fishes come from. In particular, a lot of you are curious about the mangrove communities known as "mangals." First off, a "mangal" is a term for "mangrove swamp", derived from Arabic. It's the name most commonly associated with these unique communities.

As we've discussed before, one of the defining characteristics of these mangrove communities is that they are located where fine sediments (often with high organic content) collect. They are host to a variety of organisms, ranging from algae to oysters, and continue to attract sediments in their matrix of roots. Fine, anoxic sediments under the mangroves act as "sinks" for a range of compounds, including heavy metals, and nutrients such as nitrogen and phosphorus, deposited into estuarine waters from terrestrial sources.

Because many of the mangals are intertidal- connected to the ocean and subject to tidal fluctuations, Mangroves are, by necessity, hardy plants, and can tolerate a significant, fluctuating range of salinity, temperature, and moisture, as well as a number of other varying environmental  conditions. This adaptability has made them extremely successful ecologically.

And most interesting to us as fish geeks, many fish species spend their juvenile stages in the mangals, deriving food and protection from the vast mangrove root systems. And of course, there are a variety of fishes which spend their entire lives in these unique habitats. Some, such as species of killifish and mollies, are familiar to us, while others, such as many gobies, Rainbowfishes, and even cichlids, may be somewhat less familiar. I the coming months, we'll spend more time looking at some of the aquarium-suitable fishes which occur in the mangrove habitats.

One of the defining "ingredients" of a mangrove habitat is the sediment and mud which comprise the substrate. There are a number of ways to replicate this in the aquarium, which include utilizing combinations of commercially-available sands, muds, and sediment mixes specifically intended for aquarium use. You can also experiment with terrestrial soils, such as those used by "dirted" planted aquarium enthusiasts. 

Now, to clarify our "Estuary" vision of the botanical-style brackish aquarium for a second, it should be noted that we support the use of both living and non-living materials to create both a functional and aesthetically-unique display.

We like to use dried mangrove branch wood and root sections to create the "foundational hardscape" of the aquarium, and then, enhance this by securing live mangrove propagules into the matrix. As they put down their famously long and complex roots, they will eventually "find " the substrate.Or, if you prefer, you can plant them in a fine, rich substrate from the start. They simply need to be partially submerged, and provided with bright illumination from a variety of sources.

Once they start growing leaves, you will need to spray them with fresh water from time to time to keep them from drying out and becoming caked with salt, which they release through the leaf tissues. As part of their growth, they will drop leaves from time to time, which, in our book- is a pretty cool thing, as this contributes to the biological "richness" of the aquarium as the leaves decompose! And of course, we recommend using dried mangrove leaves on the substrate, as you would in a blackwater aquarium, to further enhance this "richness!" Now, the rich substrate we advocate will also be beneficial to a variety of aquatic plants, so using specimens like Cryptocoryne ciliata and others will take advantage of this richness. 

With all of this wood and sediment, it seems like we're advocating a pretty rich, higher nutrient environment, and that's correct! Your water will likely take on a tinted appearance, of course, and  this is likely contrary to your previous experience with brackish-water systems, where the aesthetic was clear water, white sand, and rocks. We're advocating what we feel is a more realistic, functional, and more productive system for a wide variety of organisms. And, like it's blackwater counterpart, the brackish water, botanical-style system will require some monitoring of the water parameters and regular husbandry (i.e.; water exchanges, etc.) to help maintain a stable, healthy environment. 

From a purely aesthetic standpoint, the mangal can be recreated by vertically-orienting mangrove branches and roots in a deep substrate. And you have many options. If you're using a tall, narrow aquarium or a cube, you can simulate the dense matrix of the root system and the accompanying life which inhabits it.

Or, if you like, you could employ a standard rectangular, or wide aquarium and a single mangrove root aggregation on one side, to represent the area at the "margin" of the mangroves, or you could do a riparium-style tank, with a "shoreline" built up, and the mangrove roots and the planet themselves positioned accordingly. Lots and lots of possibilities for different approaches. We're excited about the ability to use traditionally more "annoying" cube-type tanks for unique applications!

Since we're talking about brackish (1.003-1.005 is our target specific gravity), you have options to adapt a lot of different fishes to this habitat. Now, if you're really adventurous, you could gradually "evolve" your aquarium to a full-strength marine environment (like 1.021-1.025) and add some interesting marine fishes, like Pipefishes, Dragonets, Seahorses, and various gobies and Damselfishes into the mix. And of course, you could begin adding some hardy corals, like Xenia, Ricordea, Pocillopora, etc., and ultimately, some "LPS" corals like Goniopora and Trachyphyllia. Oh, and Seagrasses and/or macro algae! This would be an interesting way to start a most atypical marine aquarium!  

The idea of a botanical-style brackish aquarium is to create a "platform" for all sorts of life, with the option to go in a variety of directions. In my opinion, the formerly sort of "drab" and one-dimensional brackish tanks of the past can give way to a more flexible, adaptable, and highly dynamic aquatic microcosm that can evolve into what might be one of the most diverse and amazing ecosystems you could imagine! The potential to unlock some secrets on "both sides of the salinity line" is irresistible, and the opportunity for experimentation is wide open to the intrepid hobbyist!

As more and more of our community begin working with this "methodology", the "state of the art" will definitely evolve, with techniques, ideas, and even aesthetic "styles" changing regularly. It all starts with the "mangal", and wolves from there!

We encourage you to come along for the ride!

Stay excited. Stay enthusiastic. Stay creative.

And Stay Wet.


Scott Fellman

Tannin Aquatics 




August 16, 2017


Lost in the details? Or obsessed with the mission?


I think I might be like a lot of fish geeks…I tend to dwell on really obscure minutiae. In fact, I'm kind of certain about that, based on my obsessive love for rather unusual aquatic environmental niches. I'm not sure what it is about some of these habitats that I find so compelling. Perhaps it's because no one really made the effort to do much with them, and many hobbyists were actually a bit frightened by them. In the case of blackwater, it was like, "Yeah, throw some leaves in there, the water turns brown and dirty-looking. Maybe the pH drops. It's full of unknowns and the potential for disaster..."

It was love at first sight. Sign me up! I knew that just because "everyone" said it was a bit "challenging" or "full of unknowns", that there might be a lot more to it. I mean, why were some of the most fish-rich habitats on earth comprised of blackwater? Why was everyone convinced that blackwater aquariums were a recipe for disaster? I had to play with this for myself; to research it, to act on it. Hell, I decided to build a company based on this! It was different. It was unpopular. It was unfamiliar. Perfect! It might be part of my "makeup" as a fish geek- not really sure. Maybe it's a common thing with fish geeks?

On the other hand, it's not part of my overall personality...I don't think.

I recall back in college, I was fortunate enough to land an internship in one of the hottest advertising agencies in Los Angeles- or the world, for that matter, at the time. It was so cool! As an intern, I spent time in a few different departments, even though I was “hired” for my alleged copywriting skills.

One of the departments I was relegated to was called the “Traffic” department (yeah, even the name sounded boring..), where all of the media buying, scheduling of work, and seemingly mundane (to a wannabe young copywriter, anyways) and intricately-detailed stuff was done. Translation- “boring” stuff. I remember “serving my time" in that department (yeah, that’s what my fellow interns and I called it) under a pretty crochety old advertising exec, who sort of loved and hated me at once. She’d dispense the occasional nugget of "ad-biz wisdom", followed by a verbal “bitch slap” for failing to follow her byzantine record-keeping system. Once of the best pieces of advice she ever gave me was, “Don’t ever work in this tend to get lost in the details…"

I never forgot that, BTW. And it was a true summation of me as an aquarist, too! Now, "lost in the detials" can be a good and a bad thing. I think in her assessment, this was NOT a good thing! However, when you're a fish geek, operating in the obscure niches of the aquarium world, getting lost in the minutae- even obsessed with it- is really important! And perhaps beneficial, even! Who would have known? Although at the heart of it all, I'm a very simple guy who abhors needlessly complicated stuff...

Yet, I tend to fall into that wonderful hobby tradition of not only obsessing about obscure and mostly arcane stuff, I tend to take the easy stuff and make it more complicated sometimes. And I think this is a pretty common thing among fish geeks, really. It's like this "mission" that I challenge myself to take on and complete. My hobby history is filled with examples of this. The most recent was the 50-gallon aquarium set up in my office.  For a lot of reasons, I opted for the relative simplicity of an "all-in-one" system for this tank, something in the past I simply abhorred ('cause real aquarists hate stuff being done FOR them, right? Yeah.). Yet, this aquarium is a great, open-top “AIO” system. Simple. Beautiful. Easy. 

Of course, literally right out of the box, my strange compulsion with second-guessing the designers and looking for incremental improvements kicked in! Not wanting to keep it totally “stock”, and possessing the ridiculous reefer “pedigree” that I do, I decided to change out the (shitty) stock main system pump on this all-in-one tank for a sexy, high-tech DC pump..Yeah, when you have insane "DIY-expert" reefer friends in your “inner circle” prodding you, you’re simply enabled to tweak stuff…It's like, expected.

And naturally, the connections on the tank return were completely different than those on the outlet to this pump, and I don’t want to start drilling out bulkheads and such, so I needed to get some more plumbing parts to adapt this "square peg into a round hole…" So a mere $40.00 later, there we were- a monument to aquarium absurdity! And of course..after all of that maneuvering, it wasn’t a "perfect" fit, and I noticed that the pump didn't fit well into the rear compartment, and the little rubber feet on the DC pump transmitted a little noise, so I had to line the bottom of the “sump” with some mousepad material…Another step in the process. Another layer of complication brought about by...the desire to "improve" stuff...

And the damn thing still made too much noise. The pump kicked ass, but gave me a headache in the process with that constant "hum" that every hobbyist knows is the sign of an ill-fitting pump...Something else had to give.

The best part? I ended up ultimately ditching the “sexy” pump for a tried and true Ehiem hobby pump, which is whisper quiet, as reliable as an old dog, and just- well- perfect for the application!

Simple solution. Arrived at in the most convoluted (and really f - - -ing expensive) way.

That's how serious fish geeks do it, right? We tend not to accept the solution that's been laid out in front of us. We have to modify, alter, and otherwise change stuff to meet some obscure "requirements" we have floating around in our heads. No matter what detour it might take us on.

I suppose that, for some aquarists, it’s a big part of what they love in the hobby: Setting up aquarium automation, designing and building complex auto top-off systems, wavemakers, etc. Yeah, a lot of people just love that stuff…And part of me totally gets that. I mean, yeah, I’m a lot more interested in watching my fishes and seeing them thrive and grow than I am in setting up 43 different lighting settings from my iPhone, but I really can’t fault those who do. And I respect it. I mean, where would we be in the hobby without these bold experimental types? Someone has to be the pioneer and taste the wild berries. Hopefully, they're not poisonous, right?

Me, I’m almost operating at capacity when just setting up my lighting (don’t even get me started- that’s a whole different topic for another day..).

Regardless of my challenges, I’ll occasionally come up with an idea just absurd enough to be considered rather intelligent (notice I didn’t use the word “brilliant” in any way, shape, or form..?). Some solution to a "problem" that might not be a "problem"- except maybe to ME.

You know how it goes.

I just find that, as fish geeks, we tend to get really into intricate detail on like…well, EVERYTHING!

Like, we can’t just feed our fishes…We have to utilize automatic feeding and dosing systems. We can’t just put a siphon hose in the tank like our grandparents did..Nope- we need to develop an "automated water changing system", which makes an easy task more complicated by adding  the risk of technical failure (you think that spilling a little water on your feet with a siphon hose sucks, imagine draining your whole tank..into your garage or basement…I know at least two people who managed to accomplish this with their fancy systems…Amazing insurance claims!).

On the other hand, I get a great joy out of my “old school” water change technique…something about a bucket and hose that keeps me in touch with my aquarium “roots.” Despite the temptations of technology, there are some things to me that are just sacred!

Like the "get-your-hands-wet" water change ritual. It never gets old. Even when I spill on the hardwood floor. Which, by the way, is pretty much every time.

And, as for the need to "modify" and "tweak" and make simple stuff complex than perhaps it needs to be?

It’s an affliction, maybe? Or the repressed need to gain control over our uncertain world. Maybe we just can't relax, knowing that we could "do better?" Or perhaps- it’s just part of the game, and we cannot control ourselves?

Regardless, I love every bit of it. And I know that you do, too.

And love is the basis for this whole thing. 

Spread the love. Share the ideas.

Stay inspired. Stay creative. Stay innovative. Stay complicated...

And Stay Wet.

Scott Fellman

Tannin Aquatics

August 15, 2017


Oh, what a tasty web...

If you read "The Tint" often, you know that we're really obsessed with creating really realistically functioning aquatic systems. Yes, we love natural-looking aquarium habitats, but we're equally as fascinated by replicated, or at least embracing, some of the functions which take place in the natural habitats from which our fishes come.

One of the things that we're fascinated by are what are known as "food webs."

A good description of an aquatic food web is: "...complex groups of organisms that perform different functions in the ecosystem. Phytoplankton are small primary producers suspended in water. They use nutrients along with carbon dioxide to harness sunlight energy and create biomass through the process of photosynthesis." (Source- Wikipedia)

In freshwater and many brackish ecosystems, one of the sources of "fuel" for aquatic ecosystems is leaves. As leaves drop into the water, they become food for a wide range of aquatic organisms, such as bacteria, fungi,  crustaceans, and other microorganisms which act upon them to decompose them.

And in turn, fishes feed on many of these organisms.  In fact, fungi are the key to the food chain in many tropical stream ecosystems. The relatively abundant detritus produced by the leaf litter is a very important part of the tropical stream food web.



Interestingly, some research has suggested that the decomposition of leaf litter in igapo forests is facilitated by terrestrial insects during the "dry phase", and that the periodic flooding of this habitat actually slows down the decomposition of the leaf litter (relatively speaking) because of the periodic elimination of these insects during the inundation. And, many of the organisms which survive the inundation feed off of the detritus and use the leaf substratum for shelter instead of directly feeding on it, further slowing down the decomposition.

As touched on above, much of the important input of nutrients into these habitats consists of the leaf litter and of the fungi that decompose this litter, so the bulk of the fauna found there is concentrated in accumulations of submerged litter.  And the nutrients that are released into the water as a result of the decomposition of this leaf litter do not "go into solution" in the water, but are tied up throughout in the food web of the aquatic organisms which reside in these habitats.

In some streams, there is very little internal production of food sources for their resident fishes. Rather the food sources come from materials such as plants, fruits, leaves, and pieces of wood which come from the surrounding environment. Oh, and insects. Lots of insects from the surrounding trees and bank, which fall into the water. These are known as "allochthonous inputs" in ecology- materials imported into an ecosystem from outside of it. We've touched on this idea in a recent post.

As we touched on briefly, materials such as detritus comprise a very important part of the diet of many fishes in regions such as the Amazon. Yes, detritus, the oft-vilified "enemy" of the "clean" aquarium, in many aquarists' eyes, is pretty important stuff. Think about that the next time you reach for the siphon hose! 

Now, how does all of this come together in the closed environment of the aquarium? Well, for one thing, the fungal and microbial communities which arise in our systems are likely far less dense than those in the wild habitats, where the resources are substantially greater. That being said, relative to a typical aquarium which doesn't have materials like leaves and botanicals to provide sustenance for these organisms, the botanical-style blackwater aquarium is a rich system!

With an abundance of leaves, would it not make sense that you'd see some emergence of microbial and fungal populations, functioning to some extent as they do in nature? The allochthonous inputs from our fish-feeding activities would certainly contribute to this "web", wouldn't they? And since we have the capability to impact the "productivity" of our systems based on external food inputs and the addition (or removal) of botanical materials, it seems to me that we could at least partially recreate the "food webs" associated with the systems we are trying to replicate. 

Now, my plea to the industry yet again would be to develop pure cultures of some of the organisms found in these habitats, which would not only function as food for the fishes, but, if added to the aquarium well in advance of the fishes which might prey upon them, would be able to function as they do in nature, processing fungal and microbial growth and even detritus which occur among the leaf litter.  We have bottled cultures of many saltwater copepods and such. They have become "staples" of the reef aquarium hobby for years.

(Some marine copepod products from Essential Live Feeds- one of my fave brands)

Would it not make sense for some enterprising manufacturer to develop and market these organisms for analogous purposes in the vastly larger freshwater market? I suppose it's like many other things- we need to get hobbyists to understand why they would want this stuff in their tanks! Hmm, that reminds me of what we had to do for a while when we established Tannin...!

Obscure and self-centered request notwithstanding, I really do think we'd be well-served to introduce some of the organisms (such as Gammarus, Daphnia, Bloodworms, even "Black Worms" or Tubifex) into our tanks for the sole purpose of attempting to develop at least part of a "food web." I mean, sure, it's not that simple, but to at least attempt this is a quantum leap over what has been done in this area in the past in freshwater systems (read that- essentially NOTHING!), and may at least give us some firsthand experience and insight into how these organisms can benefit our aquariums over the long term.

Now, in order to establish these organisms, you'd have to engage in the ridiculously patience-challenging practice of adding them to your tank months in advance of the fishes, to give them a chance to establish more stable populations that can resist the predation caused by the introduction of a large number of fishes. Think of the potential rewards for your patience, however!

Or, there is always the alternative of creating a "refugium" of sorts, with resident populations of these organisms safely tucked away from the main display tank, performing their leaf litter breakdown processes undeterred by the presence of hungry predators!  This is something we've done in the reef aquarium world for decades, and to my considerable dismay, the idea never seemed to catch on in the freshwater world to any great extent. And of course, one of the thought processes behind the refugium idea is that an occasional careless organism will get sucked into an intake and be deposited into the display, providing a tasty treat for the resident fishes! 

(My friend Marc maintains a pretty cool macroalgae-based 'fuge on his amazing reef aquarium...)

I firmly believe that the idea of embracing the construction (or nurturing) of a "food web" within our aquariums goes hand-in-hand with the concept of the botanical-style, blackwater (and brackish!) aquarium. With the abundance of leaves and other botanical materials to "fuel" the fungal and microbial growth, and the diligent husbandry and intellectual curiosity of the typical "tinter", the practical execution of such a concept is not too difficult to create. We are truly positioned well to explore and further develop the concept of a "food web" in our own systems, and the potential benefits are enticing! 

I hope that I've at least whetted your appetite (ewww!) for the idea with this rather cursory and choppy introduction into the concept of food webs in the aquarium! 

Stay intrigued. Stay engaged. Stay inspired. Stay on this!

And Stay Wet.


Scott Fellman

Tannin Aquatics 





August 14, 2017


Filling in some 'blank spaces" in the blackwater aquarium game...


"Don't go chasing waterfalls. Please stick to the rivers and the lakes that you're used to..." -from "Waterfalls" by TLC

Okay, I have no idea why the hook from a throwaway 1990's hip-hop song enters my head every time I contemplate writing something that displays my meager understanding of science, but this is where we are at today...I felt it oddly appropriate, actually.

So, I've had this idea for a while...

And a very brief conversation the other day with James Sheen of BlackwaterUK brought this to the forefront of my mind yet again, so I'll blame him for inspiring me to make this blatant display of my ignorance possible! :)

And, on a Monday, no less...I place my head on the proverbial chopping block in the interest of spurring more discussion and research on a topic that I think needs it!

Hello, scientists....

We talk a lot about creating and extremely rich, biodiverse habitat for our fishes, using various substrate mixes, wood, and combinations of leaf litter and aquatic botanicals. Now, we've reviewed extensively the impacts, good and bad- of building up such litter beds in our existing aquariums in this column. We've oft-repeated our plea to go slowly and judge the impact of the additions of the new materials on the water chemistry and other parameters of the aquarium and it's inhabitants. 

What we haven't discussed much is the potential utility and impact of starting a new system with  a significant amount of botanical materials from "day zero." I mean, with a lot of decomposing material which essentially function as bioload in the system, would this create a more rapid or prolonged initial break-in period? Would the tank cycle more quickly, slower, or not at all? 

It's something that we discussed briefly before, and it's kind of interesting, really. Especially in the lower pH arena in which we tend to play. I think that the occasional bad outcomes we have are a result of misunderstanding or miscalculating the effects of identification and such in our lower pH, botanical-style blackwater aquariums.

I think it starts with pushing it too hard when it comes to denitrification.

In lower pH systems, an entirely different class of organisms, known as Archea, perform the role of denitrification more traditionally associated with Nitrosomanas and NitrobacterArchaeans include inhabitants of some of the most extreme environments on the planet. Some live near  vents in the deep ocean at temperatures well over 100 degrees Centigrade! Others reside in hot springs, or in extremely alkaline or acid waters. They have even been found thriving inside the digestive tracts of cows, termites, and marine life where they produce methane (no comment here)  They live in the anoxic muds of marshes (ohhh!!), and even thrive in petroleum deposits deep underground.

Yeah, these are pretty crazy-adaptable organisms...The old sayings that "If these were six feet tall, they'd be ruling the world..." sort of comes to mind, huh?

With their incredible adaptive nature, Archea can cycle a low-pH aquarium, and reach significant population densities once they get going. The whole idea is for them to have sufficient time to build up a population which can tackle the ammonia produced by the bioload of the aquarium. And ammonia, the nastiest byproduct of the cycle, can be in two forms. Toxic (to the fish) ammonia ( NH3)  occurs when the ph is greater than 7.0.  Ammonia occurs as "non-toxic" (okay, maybe "less toxic" is a more responsible descriptor?) ammonium when the ph is below 7.0. And we certainly have to consider the impact of ammonia on our systems, right?


With the traditional nitrification cycle, there are a couple of important requirements: An anoxic environment-  It is only when the dissolved oxygen is depleted that denitrifiers begin using nitrate for respiration, which begins the denitrification reaction. The other requirement is for a sufficient amount of organic carbon to be present, and this is typically found in abundance in a new aquarium filled with stuff like botanicals, etc.

What a lot of aquarists who run very low pH systems report is that the "cycling process" takes longer to complete. This definitely correlates with my personal findings, although I've personally never managed a system with a pH much below 5.5 pH; this is where the "outer limits" of low pH aquariums starts for most, and this is the realm of Archaea, as the Nitrosomanas and Nitrobacter barely function at that point. And once again, the key ingredient to managing a low pH system (like any system) is our old friend, patience! It takes longer.

At very low (aquarium-context here) pH, water quality management is essential. This consists largely of water changes, use of chemical filtration media as required, and very slow additions of animals- and botanicals- to the system. Things like biological oxygen demand (BOD) and the ability of a biological filtration system to tackle increases in bioload are far more critical at these lower pH levels. Small, consistent moves are important.

So, this admittedly spotty look at the nitrogen cycle sort of takes us full-circle back to my thoughts about a brand new tank and botanicals. I'm thinking that if you're the the who wants to go with a large amount of botanical materials (leaves, pods, etc.) from the start- from "day zero"- that you should do this without any preconceived notion about adding fishes for a while. I'm thinking that a true "fishes cycle" IS possible with a heavily-laden botanical aquarium, as these materials most definitely constitute a "carbon source!" And I suppose that "hyper-loading" all of this stuff (if you're doing it that way) in a fishless tank from "day zero" is the responsible way to go about it.

Of course, I base this purely on "experiments" I've done with tanks set up in this fashion, and with the positive results I've seen by being patient. Oh, and a fair amount of good-old speculation. See, I told you I'm opening myself up for mass criticism from scientifically-minded hobbyists today. Well, someone has to at least get the discussion started, right? I have no properly-constructed experiment done, with controls and such, to prove anything beyond the shadow of a doubt, so it's all theoretical at this point. However, I think that, for those who are not afraid of this kind of stuff, some properly constructed experiments could prove very beneficial!

I suppose, however, for most of us, we'd start a new tank or an existing one with a reasonable amount of botanicals and gradually add/replace as necessary. This certainly gives the bacterial populations more time to adjust to the increase in bioload, and for the dissolved oxygen levels to stabilize in response to the addition of the materials added-especially in an existing aquarium. Going slowly when adding are botanicals to ANY aquarium is always the right move, IMHO.

"OMG, Fellman! Patience. We get it!"

And for those of you who are fascinated by the naturally-occurring low pH blackwater systems of the Amazon, like me, I leave you with this interesting tidbit from one of my favorite scholars on these natural habitats, Peter Alan Henderson, from a survey he conducted of a leaf litter system in an Amazonian blackwater stream:

The stream was of the typical blackwater type with a pH between 2.8 and 3.5, the lower figure being lower than any previously recorded for this water type. Leenheer (1980) attributes 85% of this acidity to organic acids and the rest to CO2. Given the low level of inorganic ions in solution the acidity must certainly be due to organic compounds. However, humic acids which are fre- quently assumed to be the major constituent are not strong enough acids to produce such a low pH. A possibility is that fermentation within the litter banks is releasing strong organic acids such as acetic acid. In temperate regions acid waters are associated with reduced faunal diversity and fishlessness (e.g. Beamish & Harvey 1972), but we recorded over 20 species of fish, showing that naturally acidified systems can support diverse fish faunas. The exceptional acid tolerance of Amazonian fish has been discussed by Dunson et al. (1977).

That's a lot to digest, but very, very interesting, right? Now the pH level in this stream is well below anything a sane aquarist would attempt to recreate in his/her tank, yet the implications and ideas expressed in the passage are tantalizing, aren't they? Fermentation! Woah. Further, he speculates that "...given the pH of the water, it is likely that fungi and not bacteria are the dominant decomposers..."

So, yeah- we really are breaking new ground in our blackwater/botanical-style aquarium "practice", aren't we? Some of us push it really hard, and are dancing on a razor's edge between success and disaster. Others are more conservative, and still other aquarists playing in this realm fall somewhere in between. With so many real unknowns, and very little in the way of solid, aquarium-derived experimentation and information on the serious management of lower pH blackwater, botanical-driven systems, everyone's experiences- good and bad- are very important to the art and science of aquarium keeping. 

I've said it before and I'll say it again: This stuff isn't for everyone. The aesthetics and functions of these types of systems require real mindset shifts, careful observation, and control of our typical "aquarist compulsions" in order to be successful! Yes, patience. And yes, there is plenty of room for stuff to go wrong if we push too hard. Just like in the early days of reef keeping, or even the "high tech" planted tank specialty- we simply need to keep moving forward and experimenting; going with our "gut" in some areas, or relying on specific data in others. There will be heartbreaking failures with favorite fishes being lost. There will be spectacular successes and incremental knowledge "wins" along the way, too. This is the reality of "ground floor" operations in the aquarium world. High risk. High reward.

It's exciting. It's scary. And yes, it IS incredibly rewarding.

Glad ot have you along for the ride as we fill in a LOT of "blank spaces" in the body of work that is the blackwater, botanical-style aquarium game.

Stay brave. Stay curious. Stay patient. Stay observant. Stay undeterred.

And Stay Wet.


Scott Fellman

Tannin Aquatics 



August 13, 2017


Reverse engineering success?

Have you ever seen someone's beautiful aquarium, thought to yourself, "I really want to duplicate that in my next tank!"- and you proceed to attempt to replicate it?

Yeah, I think we've all done something like that before. It's one of those hobby "constants"- we see something someone else has done well, and we attempt to recreate all or part of it in our own systems. And why not? It's part of the "aspirational" aspect of aquarium keeping. Now, granted, you'll never fully duplicate that tank exactly like the original, but you can bring elements of it into your own design...I mean, you should, right? Why would you want to have the exact same thing someone else did?

It's the same as when we attempt to recreate wild habitats from which our fishes come. We take the elements which we find attractive, interesting, and functionally beneficial, and try to replicate them in our tanks. This is a great thing, IMHO, because it keeps us thinking about the needs of our fishes and about the components which make up their environment.

And, as we've discussed before, there is no "rule" (except maybe in some contests) which says you have to use the exact materials found in the specific habitat you're trying to replicate. The idea is to do an aesthetic and functional facsimile of the habitat. 

I recall having a few tanks over the years that, either through the result of good planning and execution, periodic tweaks, or just plain old luck, stuck out as some of the better work that I've done in the aquarium world. "Better" meaning that they had components that I'd want to play with again.

Well, looking at them now, they had a lot of "aesthetic issues", but I was able to take components of them and use them in my more recent work.

And I've always kept elements of them in my mind, telling myself, "I'm gonna do that tank again- only bigger..." or whatever. A process...

I'd "reverse engineer" which elements conspired to create such a successful tank, and work to incorporate them in my "Version 2.0" or whatever tank I was doing. I think we all do this. And we should, really. And "iterating" off of other people's beautiful work is really fantastic, right?

Some of the best tanks I ever had, success-wise, were simply as a result of "benign neglect", or as one of my friends used to say- "letting Nature take it's course." You know, planting the tank and just letting the plants grow, not "messing" with stuff too often. Oh, sure, I'd conduct water changes and such, but that was about it. These were almost "jungle-like" in appearance, with killifish fry all over the place...really successful, cool systems for their intended purpose. I did a number of fry grow-out tanks in this fashion, and loved them each and every time.  And I learned a lot about management of aquarium systems with these "jungles", too. 

In a way, the blackwater, botanical-style aquariums that we allow to evolve "uninterrupted' to a certain extent are the absolute embodiment of this idea. There is much to be said for starting with a great "foundation" and allowing nature to do what it's done for eons. And replicating our own work by simply setting up a system in such a way as to accommodate this process is a classic example of successful aquarium "reverse engineering", isn't it? 

I'm probably rambling a bit too much on a topic that doesn't need as much explanation as I'm giving it. However, I receive a lot of correspondence from hobbyists who want to create aquariums with certain elements in them from other tanks they've tried, and wonder if the botanicals and such will work with them. I say, "Of course they will!" I mean, the reality is that you can incorporate all sorts of approaches (within reason) into an aquarium, and it may take you in any number of directions.

And that, in my opinion, is one of the joys of aquarium keeping. "Cherry-picking" elements from systems that we love or worked well for us in the past, and incorporating them intentionally in a new tank is always fun. It's how we progress, learn, develop technique, screw stuff up, and generally advance the state of the art in aquarium keeping.

And it's pretty damn fun, too.

If you're not already, don't be afraid to reverse engineer in your aquarium efforts. You just never know what might come of it! 

Stay excited. Stay curious. Stay experimental. Stay adventurous.

And Stay Wet.


Scott Fellman

Tannin Aquatics 

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