February 18, 2018


Adrift in the current...

On Friday, we talked about water clarity, which proved a lot of interesting discussion. And of course, it got me thinking about what we see in our tanks on an everyday basis.

Not long ago, I was amusingly distracted watching my office aquarium, observing a little piece of leaf floating about in the current. I don't really know why, but it somehow made me ponder how different I have approached virtually everything in my botanical aquarium than I do in any other one I keep.

One of the things you get used to in a botanical-themed aquarium is, of course, decomposing leaves, softening botanicals, and the occasional strand of biofilm. And with these things, occasionally, a piece will break off and float around in the current...I remember in years past, in my reef tanks, or "clearwater" FW tanks, I'd be incredibly aggravated by little bits of "stuff" floating in the water column, and would pretty much drop whatever I was doing and reach for the net to remove the offensive material, whatever it was.

However, when I started playing with the blackwater, botanical-themed tanks, I realized that seeing the occasional bit of debris (typically leaves or "shells" of botanicals) didn't aggravate me in the least. In fact, I found that I kind of like it. I've watched enough of Ivan Mikolji's videos and seen enough of Mike Tuccinardi's pics of natural blackwater habitats to accept that the dynamic in nature is that, well- occasionally, there is "stuff" floating in the water.

And you just have to accept this in an aquarium that utilizes these natural materials.

Now, it doesn't mean that it's cool to have uneaten food, or huge pieces of leaves, dead fishes and such floating about in your tank. However, it does mean that little bits of stuff  sort of "goes with the territory" of what we do, and that this is nature. This is what happens in the wild, and there is no particular reason why it isn't acceptable to see it in our aquariums from time to time.

Again, it's one of those "mental; shifts" we have to make, understanding and appreciating the fact that the "aesthetic" of a blackwater/botanical aquarium is far different from the "nature aquarium" that has been presented to us in the aquatic press for so long. 

It's not an excuse for sloppy husbandry, or neglecting the removal of offensive materials. However, it IS a sort of acceptance of the fact that "stuff happens" in nature- and in aquariums- and that many of these things are simply not worth getting upset about. I mean, if you have an aquarium with brown water, and substrate dominated by decomposing leaves and softening botanicals, it shouldn't come as any surprise that an occasional piece might break off and float around before settling somewhere else in the aquarium. 

I find it strongly relaxing; oddly amusing, actually. Perhaps..maybe, these transient, ephemeral moments are the exact embodiment of the idea of "wabi-sabi" that Takashi Amano wrote about so often?

Just another nuance; another little transient thing- another mental shift we have to make when keeping one of these amazing aquariums.

Going with the flow...literally. Not stressing..just accepting. And appreciating.  Think about THAT the next time you see a little pice of leaf in the current...

Stay relaxed. Stay engaged. Stay appreciative. Stay obsessed..

And Stay Wet

Scott Fellman

Tannin Aquatics 

February 17, 2018

1 comment

Eyes open..hands wet...

As I've been inching painfully towards finally getting my office brackish water aquarium wet, I reflected briefly on some of the options for equipping the tank, and how I was going to approach managing it. There was a very tiny part of me who was actually thinking of "gadget-ing up" this tank...And of course, I decided instead to be sensible about it and mix "old school"/"new school" tech.

And since this think has been inching along more slowly than NASA's Space Launch System, I think it makes more sense to go with this combination!

Technology is important. It's super beneficial for our hobby. However, it also  carries with it some additional considerations that you need to contend with...It's never simply "set and forget"- no matter how good your equipment is.

Case in point:

I had a friend call me a while back regarding some issues that she was having with her fabulously-equipped, obscenely expensive 200 US-gallon "mixed reef" aquarium. She’s got the usual littany of high-tech reef toys- high-end German-engineered protein skimmer, kalkmixer, calcium reactor, electronically controlled water pumps, and a sophisticated electronic controller that would make NASA jealous!

Seemed like all was good, and that she should have been at the top of her game with her $10,000-plus USD investment, right? Yet, for some reason, her system just didn’t look right. We've all been there, huh? In her case, her corals seemed off-color, fish were sort of listless, and the system just didn’t look “right”. You know, after you've been in the aquarium game for a while, you can just "tell" when things don't seem right!

Of course, we went through the usual questions: “Any new fishes added recently?” , “Dose any additives?”, "Changed your maintenance procedures lately? “When was the last time you did a water change?”….As it turned out, she felt that her super high-tech system made her exempt from basic husbandry practices…Not an uncommon malady in the splashy reef aquarium world.

Not only had it been literally months since she did a water change, it had been an equal number of months since she checked the probes on her controller!  You know, the expensive, useful, and obscenely high-tech device that she charged with "managing" her whole system, with lots of numbers and lights and stuff.

Upon inspection, it turned out that one of her controller’s probes cracked, and the redox probe was not even submersed in the water!  Her super system was operating with incorrect information, and environmental adjustments that were not necessary (i.e.; ozone injection and adjustments to buffering) were being made. Fortunately, we stumbled on this before things got out of hand and fishes and corals started dying. It was surprisingly easy "fix" from a technology standpoint- just replace it...

However, it was a more difficult one, philosophy-wise.

For all of her "techno-props", my friend overlooked some basic tenants of "postmodern" aquarium-keeping, freshwater, reef, or anything in between:

1) You can’t blindly rely on gadgets to control your system without glancing at them occasionally to ascertain if they are working correctly.

2) You need to adhere to some very basic husbandry practices- such as water changes, to dilute metabolic waste products, regardless of the technology you employ.

3) Know what "normal" is for your aquarium and its inhabitants. That involves more than just looking at numbers. It involves engaging all of your senses- sight, sound, smell. That..."feeling."

Basic stuff, yes- but vital if we are to enjoy long-term success with captive animals. We can't lose that "touch" we've developed as hobbyists over the past century or so of aquarium keeping, just because we have some high-tech gadgets to take away some of the "onerous" manual practices we engage in to keep an aquarium. 

I’m frequently blown away how seemingly "advanced" hobbyists tend to overlook the most basic aspects of aquariology- observation of their systems and attention to regular husbandry.  It's like a technological "dependency disorder" or something! I literally know hobbyists how have spent enough on their aquarium to purchase a small car yet cannot figure out anything about what's going on in their tanks beyond the numbers reported on their wi-fi-enabled controller readout.

And even then, they don't really know what to make of them!

This is a scary practice that has to stop! I know at least two people who have experienced outright disasters which could have been easily prevented had they simply "gotten their hands wet" from time to time. Having technology is great, but it shouldn't become a substitute for the "art" of aquarium technique.

Otherwise, we're "aquarium monitoring technicians" instead of aquarists! That sounds more like a job than a hobby to me. Technology out of control! Or is that, in TOTAL control! Er, whatever, you know what I mean.

For those of you who are heading this way and know this- or if you know someone that is-and I think you might, a plea: If you know you or your fellow hobbyist is a little deficient in the actual "practice" of aquaristics- less time should be spent shopping for that “limited edition” coral or crazy-rare cichlid,  and more time just looking at the aquarium!

Get you or your fellow hobbyist back in touch. A beautiful return to the basic “core” experience of keeping an aquarium, and get involved with the system on a more intimate level.

Our fishes, your investment- and the hobby itself- need you and your full attention.

Get your hands wet!

Stay focused on the right stuff. Stay in touch. Stay engaged.

And please...Stay Wet.


Scott Fellman

Tannin Aquatics

February 16, 2018


What exactly does "clear" mean, anyways?

As aquarium people, we were pretty much "indoctrinated" from the start that our tanks should have "crystal clear, blue-white water", and that this is one of the benchmarks of a healthy aquarium.

And of course, I won't disagree that clear water is nice.

I like it, too...However, I would make the case that "crystal clear" water is: a) not always solely indicative of "healthy" or "optimum" , and b) not always what fishes encounter in nature.


Of course, in the aquarium, "cloudy" water is often seen as indicative of some sort of trouble- typically, bacterial blooms, algal blooms, incompletely washed substrate, etc, so we correctly make the initial assessment that something might be amiss when water suddenly becomes cloudy or 'murky", or just shows turbidity.

On the other hand, "turbidity", as it's typically defined, leaves open the possibility that it's not a negative thing:

 "...the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air..."  

What am I getting at?


Well, think about a body of water like the Rio Negro. This water is of course, "tinted" because of the dissolved tannins and humic substances that are present due to decaying botanical materials.  We know all about that, right?

Yet, that's different from being cloudy or turbid, however.

And, of course, there might be some turbidity because of the runoff of soils from the surrounding forests, incompletely decomposed leaves, current, rain, etc. etc.

None of the possible causes of turbidity mentioned above in these natural watercourses represent a threat to the "quality", per se. Rather, they are the visual sign of an influx of dissolved materials that contribute to the "richness" of the environment.

It's what's "normal" for this habitat. 

 Obviously, in the closed environment that is an aquarium, "stuff" dissolving into the water may have significant impact on the overall quality. Even though it may be "normal" in a blackwater environment to have all of those dissolved leaves and botanicals, this could be problematic in the aquarium if nitrate, phosphate, and other DOC's contribute to a higher bioload, bacteria count, etc.

Again, though,  I think we need to contemplate the difference between water "quality" as expressed by the measure of compounds like nitrate and phosphate, and  visual clarity.

Our aesthetic "upbringing" in the hobby seems to push us towards crystal clear water, regardless of whether or not it's "tinted" or not. And think about it: You can have absolutely horrifically toxic levels of ammonia, dissolved heavy metals, etc. in water that is "invisible", and have perfectly beautiful parameters in water that is heavily tinted and even a bit turbid.

That's why the aquarium "mythology" which suggested that blackwater tanks were somehow "dirtier" than "blue water" tanks used to drive me crazy.

Color alone is not indicative of water quality for aquarium purposes, nor is "turbidity." Sure, by municipal drinking water standards, color and clarity are important, and can indicate a number of potential issues...But we're not talking about drinking water here, are we?

I've seen plenty of botanical-influenced blackwater aquariums which have a visual "thickness" to them-you know, a sort of look- with small amounts of particulate present in the water column- yet still have spot-on water conditions from a chemical perspective, with undetectable nitrate, phosphate, and of course, no ammonia or nitrite present.

It's important, when passing judgement on, or evaluating the concept of botanicals and blackwater in aquariums, to remember this. Look, crystal clear water is absolutely desirable for 98% of all aquariums out there- but not always "realistic", in terms of how closely the tank replicates the natural environment.

And of course, by the same token, a healthy botanical- influenced tank may typically not be turbid, but that doesn't mean that it's not "functioning properly." Again, this realization and willingness to understand and embrace the aesthetic for what it is becomes a large part of that "mental shift" that we talk about so often here on these pages.

And the beauty of an aquarium is that you can either remove or contribute to the color and clarity characteristics of your water if you don't like 'em, by simply utilizing technique- ie; mechanical and chemical filtration, water changes, etc.

It's that simple.

In summary, I submit that the key takeaway here is that we should evaluate the "health" or normalcy of a blackwater, botanical-influenced aquarium-or ANY aquarium, for that matter- based on it's chemical water quality first and foremost, AND the clarity of the water on a secondary basis (Keeping in mind, of course, that the "aesthetic" of such an aquarium may indeed mean that turbidity is perfectly normal).

A lot to think about on a relatively mundane subject- one which for many years was very "cut and dry."

Stay open-minded. Stay curious. Stay observant...

And Stay Wet.


Scott Fellman

Tannin Aquatics

February 15, 2018

1 comment

Avoiding the dreaded algae "freak out"- looking at the "bigger picture."

Have you ever completed an aquascape and stepped back and looked at it in its most "embryonic" phases, and thought to yourself, "This looks good?" The pristine glass, perfect deal wood, sparkling gravel...The scent of a brand new aquarium...

Well, of course you have! It's part of the game.

It's a total sensory experience, isn't it?

To me, the real "magic" in an aquarium happens not when it's new and pristine, but after a few weeks or months, when it develops that "patina" of micro algae, the "matte" sheen of biofilm on the substrate...when it develops that earthy, clean, alive smell.

That, to me, is when an aquarium really feels "alive" and evolving.

When it comes to maintenance of aquariums, I'm a big believer in removing algae from the front glass and "excessive" films from the driftwood or other materials...But I don't go crazy about it like I used to. Like many of you, I let some of those natural processes evolve, just like the tank itself...

I think I tend to spend less time and energy removing "offensive" algae growth manually, and spend far more time and energy controlling and eliminating the root causes of its appearance: Excess nutrients, too much light, lax maintenance practices, etc. It's not that I don't think I should be scraping algae- it's just that it seems to make more sense to "nip it in the bud" and attack the underlying causes of it's growth.

Although I love my soft-bristled toothbrush-cum-alagal-film-scraper!

Understanding the dynamic in a closed aquarium system is really important.

There is another aspect to appreciating it: Letting a system "evolve" and find its way, with a little bit of guidance (or botanicals, as the case may be) from time to time, is beautiful to me...Watching the "bigger picture" and realizing that all of these "components" are part of a bigger "whole."

This was a definite of mental shift for me, right along with accepting the biofilms, blackwater, and decomposing leaves. Like most of you, I've spent much of my fishy "career" doing "reaction" style aquarium maintenance, breaking out the algae scraper at the first sign of the "dreaded" stuff.

And I've come to realize that taking a more proactive, understanding, and yeah- relaxed approach to "algae management" has created a much more enjoyable hobby experience for me. And being a bit more accepting about seeing "some" algae growth and such has created far more aesthetically pleasing, naturally-appearing aquariums.

There is nothing wrong with creating a more "clinically sterile-looking" aquarium. Perfectly manicured, impeccably groomed task are beautiful. It's just that there is something about the way nature tends to do things that seems a bit more satisfying to me. 

And apparently, for many of you, too!

The beauty is that, like so many things in this hobby- there is no "right" or "wrong" way to approach something as mundane as algae growth and tank "grooming." It's about what works for YOU..what makes you feel comfortable, and what keeps your aquarium healthy.

Regardless of what approach we take, natural processes that have evolved over the eons will continue to occur in your aquarium. You can fight them, attempt to stave them off with elaborate "countermeasures" and labor...or you can embrace them and learn how to moderate and live with them via understanding the processes.

And the algae?

It'll always be there. It's just a matter of how "prominent" we allow it to be.

Simple. And, actually- sort of under our control, isn't it?

Stay engaged. Stay focused. Stay calm. Stay open-minded.

And Stay Wet.


Scott Fellman

Tannin Aquatics


February 14, 2018


To blur the lines...


It's a sexy hashtag that we've embraced over the years for Tannin- it sounds cool. Yet, it's one which, in my opinion, captures the ultimate "essence" of our philosophy.  A way of capturing aspects of nature in our aquarium in a manner that accepts it as it is, rather than how we want it to be.

Simplicity. Complexity. Creativity. Transience. "Randomness."

We receive so many PM's, emails, phone calls, and other inquiries from hobbyists when we run pieces featuring pics and discussions about natural environments as topics for modeling our aquaria, excited about the details and how they can be replicated in an aquarium, that it's not even funny!

And every aquarium pic that is shared  by our community, which utilizes elements of nature in a similar matter is studied, elevated...even adored- as a representation of the genius of nature.

It makes sense.

In my own rebellious way, I can't help but think that part of this enthusiasm our community has for this stuff is that most hobbyists in general have a bit of a rebellious streak, too, and that maybe, just maybe- we're a bit well, "over" the idea of the "rule-centric", mono-stylistic, dogmatic thinking that has dominated the aquascaping world for the better part of a decade.

Maybe it's time to look at nature as an inspiration again- but to look at nature as it exists- not trying to sanitize it; clean it up to meet our expectations of what an aquarium is "supposed to look like." And by the same token, not going to the other extreme-trying to validate every twig, rock, and plant in a given habitat, as if we're being "scored" by some higher power- a universal "quality assurance team"- which must certify that each and every rock and branch is, indeed from the Rio Manacapuru, for example, or your work is just some sort of travesty.

Not that there is anything wrong with this pursuit, or that I take any issue with talented hobbyists who enjoy that route. I identify with them more than the "high concept" aquascape crowd for sure! I'm just curious if there is a "middle ground" of sorts where nature is the primary influence, and accepting it and attempting to replicate it "as-is" becomes the goal.

I think that there is.

It's time to take inspiration from the reality of nature, not just its "essence."

Maybe it's time for us to once and for all accept that things are not aesthetically "perfect" in nature, in the sense of being neat and orderly from a "design" aspect. Understanding that, yeah, in nature, you have branches, rocks and botanicals materials scattered about on the bottom of streams in a seemingly random, disorderly pattern. Or are they? Could it be that current, weather events, and wind distribute materials the way they do for a reason? Could we benefit from replicating this dynamic in our aquariums?

And, is there not incredible beauty in that apparent "randomness?"

Now, I realize that a glass box is NOT a flooded Amazonian forest, mangrove estuary, or Asian peat bog. I realize that we're constrained by size and water volume. However, it can look and function like one to some degree, right? The same processes which occur on a grander scale in nature also occur on a micro-scale in our aquariums. And we can understand and embrace these processes as an essential part of the aquatic environment.

Accepting the appearance of biofilms, murky water, algae, decomposing botanical materials, and that these things occur in our aquariums, too, and can be managed to take advantage of their benefits. You know, as supplemental food sources, "nurseries" for fry, and as interesting little ways to impart beneficial humic substances and dissolved organics into the water.

Please don't misunderstand me here.

I'm not attacking "the establishment" and saying that every perfectly manicured competition aquascape sucks. I'm not saying that if a tank doesn't have blackwater, biofilms, and brown leaves that it's "uninspired." I'm merely questioning the high level of esteem which the broader aquascaping world seems to attach to conforming to some rigid style, replicating the work of others, and being rather close-minded to the work of hobbyists who try truly different things.

Some of the most amazing comments we receive after sharing underwater pics of the wild habitats of Amazonia and elsewhere are from hobbyists who, at first, thought that some of these pics were from someones' aquarium! In a few instances, some of the close ups of botanical-themed aquaria are virtually indistinguishable from wild scenes!

That says a lot. 

What an incredible dynamic!

Blurring the lines between nature and the aquarium, at the very least, from an aesthetic sense- and in many aspects, from a "functional" sense, proves just how far today's hobbyists have come...how good you are at what you do. And how much more you can do when you turn to nature as an inspiration, and embrace it for what it is.

I'm not telling you to turn your back on the modern popular aquascaping scene; to disregard or dismiss the brilliant wolf being done by aquascapers around the world, to develop a sense of superiority or snobbery, and conclude that everyone who loves this stuff is a sheep...


Not at all.

I'm simply the guy who's passing along the gentle reminder from nature that we have this great source of inspiration that really works! Rejoice in the fact that nature offers an endless variety of beauty, abundance, and challenge- and that it's all there, free for us to interpret it as we like. It's not all perfect "rule of thirds" or flawless layouts and such.

Some of us just happen to like things bit more "natural" than others...

Blur the lines.

Continue to take pride in what you do.

Don't let dogma and the prevailing mindset of  "what's cool" distract you from doing what you love and believe in. Embrace, enjoy, and accept the thoughts, attitudes, and works of others, while constantly questioning and striving to do what moves you.

Find what makes your heart sing, and do it. You'll never be "wrong."


Stay on course. Stay bold. Stay inspired. Stay humble. Stay fascinated.

And Stay Wet.


Scott Fellman

Tannin Aquatics

February 13, 2018


With fronds like these...

One of the best parts about playing with blackwater, botanical-style aquariums is that we've tried all sorts of interesting materials in our hardscapes. It's no longer a mindset of, "Throwing _____ in your tank is weird!" Now, it's more like, "Has anyone tried________ before?"

How can I not love this stuff? 

I know we've talked about food webs" in our botanical-influenced aquariums, and some of us are starting to experiment with incorporating items like small aquatic crustaceans and worms (e.g., Daphnia and "Black Worms", etc.) into our "pre-stocking" regimens, and this is creating some interesting results!

What interests me of late is the long-term "functionality" of our botanical aquariums, not just from an "environmental" perspective, but from the standpoint of supplemental food production.

We read a lot in scientific papers about fungal and microbial growth of organisms in wild leaf litter beds, and I am pretty confident that some of the same processes occur in the leaf and botanical beds we create in our aquariums.

Obviously, some fishes utilize these materials as part of their diets at some points in their lives.

We've postulated that fry will certainly make use of many appropriately-sized organisms which occur naturally. We may, at some future point, even get a feel for which botanical materials can do the best job at fostering these sorts of populations...perhaps, a different way entirely to look at the way we select and employ botanicals in our systems!

Like, selecting certain botanicals specifically for "cultivating" microorganisms and small crustaceans to use as supplemental food sources for our fishes! 

I can't help but wonder if our botanical tanks, simply by virtue of the fact that they have accumulations of decomposing plant materials, foster a significant enough of a population of "edible" microorganisms for fry to consume.

In theory, I'd think so. However, the aquarist in me can't help but think that we should also consider "inoculating" our aquariums with pure cultures of organisms like Paramecium and various "infusoria" at various times during the "startup" phase of our aquarium to sort of "kickstart" the populations, if reproduction of fishes is our goal. 

And of course, part of me wonders if having a larger and more diverse population of microorganisms as "consumers" would make a more diverse and efficient botanical-style aquarium.

I think that it would.

And one of the botanicals I think about a lot lately in this context is the palm frond.

Now, with many of us playing with palm fronds of late, I can't help but wonder if, both by virtue of their surface area AND their composition, that these support larger populations of both "food" microorganisms and maybe even beneficial bacteria for denitrification.

In addition to looking good, do these materials actually help make for a more stable system from a biological standpoint? I mean, they do break down over time, but...

I would imagine that palm fronds provide interesting areas for fry to both shelter and graze upon, so it might not be a bad idea to include them in many aquariums intended to rear fry.

Other than taking up physical space, I'm not seeing a huge downside to this...that is, if you're trying to rear fry in a more "natural-type" setup, as opposed to a more sterile, functional breeding setup.

And the aesthetic they bring is nothing short of amazing!

Palm fronds are interesting from a "functional aquascaping" perspective, not only because they serve to foster beneficial life forms (and that thought of surface area for biological filtration), but from a standpoint of demarkation of territory, and serving as natural "flow deflectors", and of course, blocking out some light for fishes that prefer dim conditions (I don't know why Boraras species keep coming to mind here). I think they remind me very much of a piece of driftwood, in terms of the possibilities to support a population of fishes. 

I could envision, because of their large size, yet flexible nature, an entire community" of small fishes, ranging from Angelfish to Bettas to cichlids, to loaches, Badis, and catfishes, living out a large portion of their lives in and among submerged palm fronds. The sense of protection and the easy availability of food could really lead to some interesting, natural behaviors in our fishes...particularly the really small fishes that certain individuals among us favor... 

So, a palm frond as a habitat area is most intriguing to me,almost a sort of "freshwater reef", really.

And I can visualize various behaviors and other aspects of our fishes being influenced by these items in their environment. No doubt palm fronds have some ecological role in nature that benefits fishes.

Those of you that have also begun experimentation with palm fronds are telling me not only are you intrigued by these ideas as well, you're also loving the aesthetics they bring!

I suppose it would be easy for some negative types to simply call our recent infatuation with Palm fronds as a sort of "trend", but the reality is- it's more of an evolution of what we've been doing with botanical aquariums: Incorporating different materials in different ways; evolving both technique and aesthetic as we go.

Much groundwork has been laid by hobbyists like Rene Claus and Tai Strietman, who have played with palm fronds for some time, and much credit should be given to them for leading the way!

Like so many things in our evolving world of botanical, blackwater aquariums, embracing natural processes and behaviors is best amplified by embracing natural materials, utilized in different ways.

With form, function, utility- and all sorts of possibilities in between, Palm fronds are here to stay, in my opinion, as a "tool" in our botanical toolkit...

And if our fishes (and microbial populations) could talk, I imagine they'd be inclined to agree!

That's a "win-win" in my book!

Stay excited. Stay creative. Stay experimental. Stay engaged.

And Stay Wet.


Scott Fellman

Tannin Aquatics 








February 12, 2018


What botanicals won't do...clearing up a few assumptions...

With all of the cool tanks we're seeing coming up, and a growing global interest in blackwater, botanical-style aquariums, we're seeing a lot of discussion about the "functional" aspects of botanicals. And with all of the discussion comes a little confusion, a lot of information, and some occasional misconceptions about what botanicals can do for our aquariums.

Today, I'd like to focus on what botanicals CAN'T do! Or at least, what they can't do as completely as many hobbyists tend to assume that they can! We're just gonna look at three things- but these are topics which seem to come up again and again, so I feel there worthy of a closer look.

Yeah, it's very important to clear up lingering (or emerging) misconceptions about the use of botanical materials in aquariums. As in so many areas of the hobby, the more people become involved in the process of utilizing them in their aquariums, the more we break through and clear up some of the confusions about them...And it's not like anyone was intentionally trying to mislead people over the years- I think it was more of a matter of us just making lots of assumptions and drawing conclusions from widely varying sources- often with questionable validity or accuracy.

So, in no particular order, here are some things that I think we need to address:

1) Botanicals cannot soften your water. I think it's easy to see how this one got started and tends to hang around a bit. Most botanical materials contain tannins and humic substances, which can drive down the pH in water with little to no carbonate harness. And of course, the tinted, soft acidic water in many natural habitats often has an abundance of leaves and botanicals present. I think that this gave a lot of hobbyists the impression that you could simply add some of these materials (leaves, etc.) into your tap water and create "Rio Negro-like" conditions easily!

Now sure, humic substances, tannins, and other compounds which color the water will be imparted to it when you add botanicals...

Yet, that's really only half of the story.

Botanicals cannot reduce the hardness of the water. This can only be accomplished with reverse osmosis or ion exchange( a process in which calcium and magnesium ions are "exchanged" for sodium or potassium ions.)

Reverse osmosis is a water treatment process which relies on a membrane which has pores large enough to admit water molecules, yet "hardness ions" such as Ca2+ and Mg2+ remain behind and are flushed away by excess water. The resulting product water is thus called "soft water"-free of hardness ions without any other ions being added. 

There is no substance you can add- natural or otherwise- directly to your water to soften it. 


2) Tinted water is not necessarily acidic. Once again, another assumption that no doubt arose from the aesthetics of blackwater itself. And it is easy to see how it got started...Much like the misconception that botanicals soften the water, it was often assumed by hobbyists that the brownish tint imparted to the water by leaves and botanicals somehow implied that it is acidic. Yes, these materials contain substances that can reduce the pH in water with low to negligible carbonate hardness.

However, the tannins, which are the substances which tint the water, cannot "overcome" the Calcium and Magnesium ions, and drive down the pH significantly in water with high levels of these carbonate hardness present. It simply is putting more materials into the water (which are often detectible by TDS meters in aquariums). And, as we've discussed before, there are natural habitats, such as the Tapajos, which have essentially clear water, yet are rather soft and acidic. 


3) Catappa leaves can "cure fish diseases." Well, this is one of the favorites which has been perpetuated for years (often by people who sell leaves online and elsewhere -hey, I'm in that group, huh?)- and it actually has some validity to it. It has been known for many years by science that botanicals like catappa leaves (and others) have substances in their tissues which do have some potential medicinal functions, like saponins phytosterols, punicalagins, etc.  Fancy names that sounds really cool- these are often bounced around on hobby sites as the "magic elixir" for a variety of fish ailments and maladies.

Now, I can't entirely beat the crap out of this idea, as these compounds are known to provide certain health benefits in humans. and for a long time, it was anecdotically assumed that they did the same for fishes. And believe it or not, there have been studies that show benefits to fishes imparted by substances in catappa and other leaves. I stumbled across a study conducted in Thailand with Tilapia concluded  that Catappa extract was useful at eradicating the nasty exoparasite, Trichodina, and the growth of a couple of strains of Aeromonas hydrophila was also inhibited by dosing Catappa leaf extract at a concentration of 0.5 mg/ml and up. In addition, this solution was shown to reduce the fungal infection in Tilapia eggs!

And it is now widely accepted by science that humic substances (such as those present in botanicals) are thought to have a wide range of health benefits for fishes in all types of habitats. We've covered this before in a great guest blog by Vince Dollar, and the implications for the hobby and industry are profound. Although they are not the "cure all" that many vendors have touted them as, leaves and other botanicals do possess a wide range of substances which can have significantly beneficial impact on fish health.

Of course, there are many others which arise from time to time- but those are "the big three" that we seem to hear about a lot. And, as we've seen, these are not entirely erroneous; however, it's important NOT to make assumptions about these materials, and to assume that they are "miraculous things" we can add to our tanks to do achieve smashing success.

The fact is, we still don't fully understand all of he affects- mostly good- but some possibly not so good- about the use of botanicals in aquariums. We have seen a LOT of instances of seemingly "spontaneous" (or at least, rather rapid) spawnings of fishes which have otherwise eluded the aquarists' efforts- shortly after introducing botanicals to their tanks.

Is this a result of some "substances" present in the botanicals? Is it a lowering of the pH in a softer-water aquarium? IS it those humic substances? Shock or some type of stress response? (!) Or could it be just a coincidence? It could be all of the above- however, I must admit that the number of times we've seen and heard this happen to us and others leads me to believe that there literally IS "something in the water!" Exactly what, of course- and how it influences these events is yet to be fully determined! 

And isn't that just the kind of stuff that keeps hobbyists coming back for more...searching, experimenting, tweaking?

Yeah, it is. And with more "technique" than ever before starting to replace the "dump and pray" method of using botanicals in aquariums, we're seeing more and more interesting results that simply go beyond just enjoying the unique aesthetics offered by blackwater, botanical-style aquariums. We're starting to see some interesting effects on the health and well-being of many species of fishes. We're learning about the value of replicating (to some extent) the natural conditions which our fishes have adapted to for eons.

And perhaps most important- we're taking a good, long look at many aspects of the precious- and often endangered- natural habitats of our fishes. This search for knowledge and appreciation of nature will not only benefit the hobby, but quite possibly the ecosystem of our home planet, as we gain a better understanding of the dynamics of blackwater habitats and the need to preserve and protect them as havens of life.


Oh, and we're having some FUN, too!

Stay bold. Stay experimental. Stay open-minded, yet skeptical. Stay diligent...

And Stay Wet.


Scott Fellman

Tannin Aquatics 



February 11, 2018


Offense/defense and the art of proactive aquarium keeping...

Today, I wanted to talk about practices which create great long-term outcomes for our aquariums. Proactive stuff.

It involves looking at our aquariums from multiple perspectives.

You've heard the time-worn sports cliches and how they apply to other areas of life...and they apply to aquarium-keeping for sure:

"The best offense is a good defense."

"Offense scores points. Defense wins games."

Well, they do. Which one is most applicable?

Both. Applied in the proper measure. At least, that's my take on it.

We need to play "defense" in our fish-keeping as much as we play offense.

"Defense", in our world, is the day-to-day things that we need to do to keep our tanks running well: Feeding fishes, observing, adjusting parameters to make sure that the system is running optimally, or reacting to a disease or other health issue of the fishes and plants, or repairing equipment, etc. "Defense", in this context, is what almost every aquarist on the planet practices on a daily basis.

Would we be better served buy investing more energy in offense?

You know, "attacking" problems proactively from the outset?

Before they become problems? I think so. It's one thing I can say was a positive gain from reef keeping: Setting up a system from the start to address the potential "what-ifs?" Reefers are really good at this sort of stuff (just look at the gadgetry and plumbing in some of those forum "tank-build threads!"), and it translates well to freshwater.

Although I've typically been a "Don't f - - - with- the- tank- once- it's- up- and- running"- kind of aquarist for many years, my philosophy has evolved a bit since I began working heavily with botanical-influenced systems. The offense-defense dynamic is more important that ever.

An example of "offense", in this context, would be setting up a new system to create an optimal environment to breed your fish. Things that are big-picture, growth activities are also "offensive." You know, selecting the proper sized aquarium, appropriate filter, heater, and other components falls into this category. In a botanical-style aquarium, much like any other, it's important to create the optimum situation to assure that the system can function properly as it evolves over time.

A mix of "defense", with a healthy dose of "offense." 

"Offense" also includes things like stocking the tank with a mix of appropriate fishes, which are compatible and capable of serving in the environment which you've created.

Making logical decisions is an essential part of the development of any aquarium, although in a blackwater/botanical-style aquarium, you need to take into account the other variables in the equation: Lower pH, the bioload of decomposing botanical materials, and the long-term maintenance of stable pH and organic levels.

We've talked repeatedly about not obsessing over target numbers, yet the importance of maintaining a tight range for most parameters cannot be understated.

What other "offensive" things can you do to assure long-term success in a blackwater, botanical-style aquarium?

We've mentioned many of them repeatedly here over the past couple of years; most are sort of automatic" to many of us now. Yet, in my opinion, there is one practice that stands out above all others in the context of our approach:

The continuous replacement and supplementation of leaves and botanicals as they start to break down. This not only creates a continuously evolving aesthetic, it helps maintain the biological diversity and environmental parameters are held in the cherished "tight range".

I know a few "tinters" who make significant replacements of leaf and botanical items and replace them with fresh materials simultaneously, and this is conducted on a regular basis. This is similar to the Japanese aquascaping practice of "sozo haishoku" espoused by Takashi Amano, which is the processs of removing of as much old substrate material as possible along with the plants it contains in an aquarium, and replacing them with new materials. It preserves the overall "composition" of the layout, but the "softscape" (botanicals and leaves, in our case) could change dramatically.

This process is very interesting to us as botanical-style aquarium fans, because, as we talked about before, it does sort of mimic what happens in many streams and rivers on a seasonal basis: Older materials are swept downstream as the watercourses swell, and are replaced by new ones that arrive to replace them. And of course, in the aquarium, performing a "sozo haishoku"-type replacement of materials can significantly change the aesthetic of the aquascape because the botanicals are replaced with different ones after the previous ones are removed.

Now, personally- I'm a fan of less "radical" moves, and in the interest of a good "offense", I favor regular additions to the botanical "set" in my aquariums. I tend not to remove any decomposing botanical material, unless it becomes an aesthetic detraction because it's blowing all over the place or something like that.

Having studied many images of Amazonian igarapes, it is very obvious that, although some materials are swept away, many remain in place until they fully decompose, adding to the richness and complexity of the habitat, and that we can mimic this process in our aquariums to some advantage.


And defense.

Working together for long term success. It's a beautiful dynamic. A beautiful game.

Massage it. Evolve it. Tweak it. Perfect it, if you can.

Stay on top of stuff. Stay observant. Stay vigilant. Stay cautious. Stay bold. Stay balanced.

And Stay Wet.

Scott Fellman

Tannin Aquatics


February 09, 2018


Emerging from the darkness. A personal story.

Today's piece is a bit more personal...it's something that I think many of you can relate to. It's about business, passion...life. People often ask me how I have such a total enthusiasm for what I do. How I can be "on" all the time? 

And it made me reflect. 

A few weeks back, 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. I felt bad for him. And I think part of the reason was because I was there before, myself.

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 was/am(?) actually rather well-known in the reef aquarium world before I started Tannin Aquatics...Oh, that sounded a bit arrogant, huh?

Might have.

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 pretty 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. It is what I was born to be. I had my first legit aquarium at age 4- no joke. And it's just mushroomed from there. It wasn't just because I wanted to be  into the hobby- I was destined for it, lol.

However, there was period of time, when , up until a few years ago, I was very peripherally involved in the aquarium hobby on a personal level...That is, actually keeping tanks of my own on any serious level. It had been only 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!

But that doesn't really count, does it?

And over that time span, as I slowly formulated the idea for Tannin, and played with more and more ideas for blackwater aquariums, I tested every product we offer at Tannin in my own freshwater tanks...came up with ideas...sourced products. But the sad reality is that I felt "disconnected" from the actual hobby, until not all that long ago.

Everything was "business."

It seemed as though my hobby was more about accumulating frequent flyer miles and seat upgrades on speaking trips than it was about accumulating relatable hobby experiences.

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. Or any passion of yours which has become a business. 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. 

I ran into this a bit when I started Tannin. It was surprisingly strong- the vitriol from the hobby's dark corners...

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 ran into this a bit when I started Tannin. It was surprisingly strong- the vitriol from the hobby's dark corners...


I realized not too many years ago that I was drifting into that 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 2010..er, 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.

Even though, on the surface, I was right there.

I'd 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 all of the major reef aquarium sites- Reef Builders, Reef2Reef, etc., been published in magazines- all that stuff. My daily “rants” and blogs were "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 mattered then is that I knew that I wanted to be myself again. A hobbyist of the geekiest type. With wet hands, towels everywhere...stuff like that.

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 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 provided 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.

And we've evolved an amazing community around  Tannin!

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. It may have been just sort of "smoking embers"- but it was there. Just waiting for a spark.

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 here in Los Angeles with him..to 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.

During that time, my idea for Tannin started to emerge...The idea blossomed into reality, because I got my hands wet again! I became ME again.


Now, when I'm putting together one of your orders, or perhaps helping a new "Tinter" decide on which botanicals to choose for her 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 a 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.

You can do this.

If you know a hobbyist who's drifting away, losing that passion...intervene. It works. This hobby is hard to get out of your system- trust me! The hobby needs talented, engaged people.

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. Don't give up on the hobby. 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

February 08, 2018


Pools, ponds, riffles, rain, and current...

Those of you who regularly read this column know that I like to reflect frequently on the "process" of evolving and changing aquariums over time. I view every interaction with our tanks as an opportunity to reflect, observe, and manage the long-term evolution of them. And if you're like me- there are LOTS of interactions with your tanks!


Thursdays are  water exchange days for my aquariums. And, rather than look at it as some task on a checklist of stuff to do, some necessary evil" chore- we regard them as... opportunities.


Yup, opportuntiies!



A water exchange represents an opportunity to refresh, reinvigorate, and interact with the aquarium on a much more detailed, intimate level. We've pointed out many times before that, in a blackwater/botanical-style aquarium, the regular water exchanges we conduct on our aquariums are, in many ways, very much a mimicry of what happens in the wild streams and rivers of the tropical world during the rainy season: New water is added to the environment, old botanical materials and leaves are swept away from their current locations, and a new set of materials are deposited in their place.


More so than perhaps other types of aquariums- the practice of replacing botanicals and leaves along with new water is a significant "weekly evolution" of the environment in this style of system.



Beyond a simple "editing ritual" or an aesthetic "refresh", this is a very dynamic process, yet one which also provides longer-term benefits for the ecosystem. Why? Because, as these newer materials are deposited, they not only help "reinforce" the matrix of botanicals already in place, they provide new physical "structure", new foraging areas, new chemical inputs (like tannins and other organics), and provide fresh material for the continued development of food webs.


Yeah, food webs- starting with microbial life and fungi, to algae, and on up to insects and crustaceans, which form the "backbone" of the diet of many of our fishes which hail from these habitats.



In nature, the rain also effects the depth and flow rates of many of the waters in this region, with the associated impacts mentioned above, as well as their influence on stream structures, like submerged logs, sandbars, rocks, etc. Much in the way we might move a few things around now and again during maintenance! 



Ever think about it like that? Yeah, it's truly amazing how we can sort of replicate these processes, simply by doing the stuff we do to maintain our aquariums! 



And stuff certainly gets moved around, re-distributed, and otherwise affected in the wild as a result of rain!


Like, a LOT!



For example, seasonal water levels can rise up to 20 meters (65 feet) in the middle Amazon region! That's a lot of water! Towards the mouth of the Amazon, the yearly change becomes less and less, but even near  the Rio Xingu, it can still be as much as 4 meters (12 feet).


This seasonal deluge has huge impact on not only the physical structure of the associated rivers, streams, and their surrounding forest terrain, but on the fishes and other creatures which reside in them.


Amazonian streams typically feature two interesting biotopes that we haven't really discussed in much detail here, and both of which are quite profoundly impacted by the seasonal rains: Pools, with slower current and a substrate covered mainly by deposits of leaf litter, detritus and driftwood; and "riffles' (defined as shallow sections of a stream with rapid current and a surface broken by gravel, rubble or boulders), with a moderately-fast-flowing current and mostly sandy bottom with tree roots, driftwood pieces, and small rocks and pebbles. (ohh...home to Darter Characins! I'm thinking cool niche biotope aquarium here...)
These "riffles" are considerably more significant in the wet season, when the obvious impact of higher water volumes are present.
And interestingly, you'll find an unexpected abundance of some species familiar to us as hobbyists in these "riffles."  Species like Pyrrhulina brevis, Hyphessobrycon melazonatus, and Hemigrammus of various forms, and even some Nanostimus, and the killie Rivulus compressus!
I find this intriguing, because we tend to associate a lot of these little fishes with sluggish water and more static environments, not areas exposed to greater current and movement. 
I pose the question once again:
Do we need to consider applying larger volumes of "intelligent" water movement to our typical freshwater aquariums?
I believe that the answer might be a resounding yes, and point to the observations about the physical habitats above as a model.
Oh, back to those Amazonian pools...
Interesting "factoid": Some scientists have postulated that the higher presence of nocturnal predators in the pools might increase the number of species that seek refuge in the riffles to avoid them!
And Rivulus, which usually live in more intermittent pools along the stream edges, outside the main stream channels, are normally found at night in these riffles!  
This makes a lot of sense, right? I mean, it's a lot harder to catch your dinner when you have to contend not with the current as well! Quite a defensive mechanism!
How can we as hobbyists use these kinds of pieces of information to create more realistic closed ecosystems for our fishes?

At the very least, I think it important to continue looking at our water exchanges and botanical additions/removals in the context of how natural bodies of water actually function.
Such a point of view will keep our minds open and senses attuned to the evolving habitat within that glass or acrylic box which our fishes call home.
Change in these habitats is constant. Adaptation by our animals to them is as well.
Interesting stuff to ponder, isn't it?
Stay observant. Stay curious. Stay creative. Stay contextual. Stay excited.
And Stay Wet.
Scott Fellman
Tannin Aquatics 
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