It's kind of my fault...An essay on the power of words, and the need to think more...

Words matter, don't they?

Okay, I have a confession to make: I think I should have never coined the term "Botanical-Style Aquarium" to describe the approach that we take to our aquariums. A lot of people are under the impression that this is some style of aquascaping our tanks.

It's not a "style" of aquascaping.

I think it's kind of my fault. The confusion, that is.

I suppose that I can explain a bit. I mean, it was important for me to "put down a marker" a few years back to explain what makes this approach different than other, more "conventional" methodologies to create and operate aquariums. I mean, we introduce botanical materials into our aquariums to help build out the physical, ecological, and chemical environment in which our fishes live.

So I tried to "quantify" it with a name.

I guess it made sense at the time.

However, the problem is that I used the word "style" as part of the descriptor...And that seems to imply that this is a "style" of "aquascaping" an aquarium- the exact thing I didn't want to do! And the term has sorta stuck.

Yet, it's so much more than a "style", isn't it? 

Yes, it is. It's a methodology.

An approach to creating and managing a specialized aquatic ecosystem within the aquarium, for the benefit of the fishes which are accustomed to these types of habitats in Nature. Perhaps it should be called the "botanical-method aquarium?" Well, that doesn't sound as sexy. There must be a better way to say it? A word that's less open to (mis)interpretation? Likely.

And yet, I used the damn word, "style"- arghhghhghhhhh!😂

The, and always was, to look at Nature differently than we have in the past as aquarists. It's a fundamental shift in how we keep aquariums. For way, way too many years, the hobby has preached a sort of "edited" or "sanitized" version of Nature. 

Aquarium hobby "doctrine" has implored us to keep things "clean" and to discourage the accumulations of organic detritus, to remove decomposing materials, keep our water crystal clear and "invisible", and to vilify and remove algae whenever it appears.

Speaking of "Nature", it's another term that we in the hobby seem to have appropriated for whatever suits us...and it's confusing, too.

The term "Nature", like "style" seems to be interpreted differently by different people in the hobby, and it's important to understand this. Words do matter, right? Or, perhaps how we interpret words matters...

The problem with using the term "Nature", as I see it, is that we have engaged in sort of selectively picking and choosing what our hobby culture considers the "good" parts of Nature, and editing, downplaying, and resisting those which don't fit the "guidelines" set by the hobby hegomony.

Okay, perhaps I'm being a bit harsh. But it's for a reason.

Consider this:

Over the century or so of the modern hobby, a lot of hobbyists and authors have espoused embracing of natural process and have sung the praises of algae; stuff like that. I'm glad they have. However, the modern "successful aquarium", as currently presented to us in books, magazine articles, and social media, is almost always depicted as this perfectly manicured, scrupulously clean box full of water.

Sort of not exactly "natural"- or is it? A strange dichotomy.

And props to the late Takashi Amano, who, in his early essays, encouraged us to embrace this stuff when we create aquairums...only to have, IMHO "popular aquarium culture" grab and run with the "art part" of his equation at the exclusion of almost all else, conveniently assigning many of Nature's most compelling natural processes to the metaphorical "dustbin", while celebrating symmetry, color grouping, wood placement, and weirdly-named rock selection instead.

Tragic, IMHO. 

Let's be more precise and thoughtful when we use words like "natural" to describe our tanks.


(Random "Micro rant" alert...):

And don't even start me on the latest aquascaping craze of gluing pieces of wood to rocks...I mean, what about gravity and...patience? Like, find the right rock and wood! I know, everyone hates me for criticizing this practice but, damn.. If it were done to create something that actually looks natural, I'd maybe be more on board with it... You can do weird, natural-looking stuff with skillful application of wood to rocks...But glue? Really? And, do you see some of the stuff people do when they glue rocks and wood together? It's weird, and much of it hardly looks "natural" to me. Maybe in "middle earth" or wherever aquascaping contest judges live, this is "natural", but...

Like, what planet did that shit "form" on? 

Okay, enough.

"Micro rant" over.


Back to my screwup. 

"Botanical -Style" aquarium...


WTF was I thinking?

I can't help but feel like, by invoking "style", I contributed to the ongoing elevation of fluff over substance in the hobby.

Yeah, it seems to be an aesthetics over everything world in the hobby right now, which is why the terms "aquascaping" and "style" tend to evoke weird reactions in me. But that's just me, and who am I to tell the world how to play? However, it is annoying to me. 😆  Especially when people consistently use the terms "Nature" or "natural" to describe their decidedly unnatural, primarily artistic works. Just because you have plants and fish in your tank doesn't mean it's a depiction of "Nature" as it is. 

Yet, year after year, you see the latest aquascaping contest winners, often consisting of aquatic moss-bedecked, artificially-constructed "Bonsai trees" in some highly stylized underwater diorama, being lauded by the world as "an incredible "natural aquarium!"

A lot of art and not as much "Nature", IMHO. Now, there is nothing wrong with the executions. They're brilliant and skillful. And the aquarium world lauds that...but that's not all.

Anything departing from that "prototype" seems to have been systematically discouraged, frowned upon, and even vilified by parts of the aquarium community.  The problem is that the general public, who might be keenly unaware of the realities of what a natural aquatic habitat, sees these works, which are labeled as "natural"-only to perhaps never see what "unedited" Nature actually looks like.

And, to an outsider like me, it looks like the "Nature" part of Nature has become almost an annoyance, while celebrating the teachings of Mr. Amano...a strange dichotomy. The reality is that, to Mr.. Amano, Nature was the whole fucking game...

He was right. 

And then along came us.

I won't ever compare myself or Tannin to Mr. Amano; all we did was pick up the ball and run with the idea that natural processes should be studied, understood, exhaulted and celebrated, not polished out and edited to fit conveniently into our idea of what Nature should look like. If I'm nothing else, I'm the advocate for "do Nature more naturally.."


And we should be excited by this stuff: Decomposition, sediment, fungal growths, biofilms, tinted water, food-webs, and turbidity. They occur for a reason. They are part of the process and function of Nature. They impart a certain look to things, and we should accept and anticipate this as part of the "aesthetics" of this type of approach. I mean, all of those things found in the wild-happening in your own aquarium!

So, what about botanicals?

The idea of utilizing botanicals in the aquarium can be whatever you want, sure. However, if you ask me (and you likely didn't)- the idea of utilizing these materials in our tanks was to create environmental conditions and foster a biome of organisms which work together to form a closed microcosm. That is incredible to me.

It's the challenge off our times in the hobby, IMHO:

To create aquariums which, in function and form, replicate many of the wild natural aquatic habitats that we find so compelling, as closely as possible. As I've said a lot lately, the "look" is only part of the equation. In reality, the best part of the aesthetics come as a collateral result of the function of these processes...A tough way to interpret it, I know, but it's the reality we embrace.

And then there is this "blackwater aquarium" thing, and throwing botanicals into our tanks to influence the aquatic environment in the hopes of creating "blackwater." I hope we haven't added to the enormous body of lousy information that's out there on this subject. 

We might have.

First off, as I say virtually every time we talk about it, this is not a "new" concept. We had nothing to do with the "invention" of the practice. Hobbyists have been tossing in leaves and such into aquariums for many years to initiate breeding and facilitate health of some challenging fishes.  We came along and elevated the approach, studied the process, and celebrated the function, in addition to the "look." We're likely the loudest voice on this stuff right now- but no one "invented" this practice.

Maybe we played some role in this recent "awakening" of interest in this stuff; however, the whole concept of utilizing these materials to create not only healthy chemical environments for our fishes, but to create aesthetically fascinating, remarkably faithful replications of wild habitats is being given some new life thanks to the work of a global community of hobbyists- YOU!

Thankfully, the idea of blackwater aquariums being seen as a "side show" curiosity is falling by the wayside, as hobbyists are utilizing these types of tanks to keep even fishes which have been with us for decades, and achieving remarkable results...and discovering a new aesthetic and enjoyment in the process. 

And of course, there is a lot of misunderstanding about what blackwater actually is.

Black waters typically are rather acidic-more so than the typically more neutral "white waters", although color is absolutely NOT an indicator of pH. This has been confounded and confused in the hobby for years and years. "Blackwater"refers to  the color, sure- but more than just that. It's about a specific set of chemical characteristics.

The major difference between "blackwater" and "whitewater" is the lower concentration of magnesium, sodium, potassium, and calcium ions present.  Those major ions are very low in black waters. And  the concentration of humic and fulvic acids...most of which are present as a result of the geology and soils of the surrounding terrestrial environment- are not strictly from leaves and wood and such, as we have played with in our aquaria historically. 

And of course, this lack of certain major ions has some ecological implications, right? Like, it's why you don't find a lot of shrimp, crustaceans, and mullusks in blackwater habitats. It's hard to build a up a calcareous shell in the absence of calcium, right?


In the podzol soil where blackwater originates, most of the of the extractable substances in the surface litter layer are humic acids, typically coming from decaying plant material. Scientists have concluded that greater input of plant litter leads to greater input of humic substances into ground water. In other words, those leaves that accumulate on the substrate are putting out significant amounts of humic acids, as we've talked about previously!

And although humic substances, like fulvic acid, are found in both blackwater and clear water habitats, the organic detritus (you know, from leaves and such) in blackwater contains more extractable fulvic acid than in clearwater  habitats, as one might suspect!

The Rio Negro, for example, contains mostly humic acids, indicating that suspended sediment selectively adsorbs humic acids from black water.  The low concentration of suspended sediments in rivers like the Rio Negro is one of the main reasons why high concentrations of humic acids are maintained. With little to no suspended sediment, there is no "adsorbent surface" (other than the substrate of the river, upon which these acids can be taken hold of (adsorb).

This contributes to why blackwater has the color that it does, too. Blackwater in the Amazon basin is colored reddish-brown. Why? Well, it has  those organic compounds dissolved in it, of course. 

There's a lot more to it than this, but you get the idea, I hope.

And the lower pH levels that we all seem to want to target so badly require more understanding than just, "What do I add to my tank to get 5.6?" We need to study and educate ourselves on this stuff. And some of the reading we need to do is dry and perhaps challenging. However, if we don't do some of this work, we will continue to propagate (unintentionally) misinformation on the subject.

Some of the most common questions we receive here at Tannin are things like, "How much _______ do I need to get my water to look like________?" or "How much_______ is needed to lower the pH in my tank?" Or, "How much do I need to get a good amount of humic substances and tannins into my aquarium?"

Good questions. However, I usually respond with a simple, "I don't know."

These are all really good questions. Logical. Important. Yet, I kind of feel like many hobbyists are looking for a plug-and-play "formula" or "recipe" for how to achieve certain, completely predictable parameters using leaves or whatever. I totally get that. But the reality is...there IS no "recipe" for how to do this stuff at the moment.

And it sucks, I know.

And the pH thing? Again, we need to educate ourselves a bit; not just read third-hand suppositions from a guy on a Facebook group who heard that "you can't do_____" or from the vendor on e-Bay telling you that his Alder Cones "help create blackwater", etc.

Learn about basic water chemistry if you're into this idea of extremely low pH tanks. Peruse studies of natural blackwater environments and understand what influences are responsible for them. It's less easy to digest than the sexy Instagram Stories post  by "cichlidboy456" on his "blackwater tank", but it's the stuff you need to know to really understand this stuff.

We've talked a lot about the many cautions and even "myths" surrounding keeping fishes in low-pH environments. We've learned that by simply not being afraid because "they" have made them seem so scary and unmanageable for years. Rather, we're revisiting these parameters and trying to learn exactly what happens in them, and what we need know to mange them in our tanks.

It's been scientifically documented that humic substances contained in blackwater environments are essential to the health of almost all fishes, and that they enable fishes to live in these low pH habitats. We're starting to discover that creating a low pH aquarium is entirely possible and straightforward manage, if one learns the dynamics. Much like the previous generations' discoveries about the aquarium "functionality" of African Rift Lake habitats and coral reefs, we're discovering that these are simply different types of environments which can be replicated and managed long term in the aquarium.

It's not "scary"- it's just different.

Our understanding of the nitrogen cycle and the toxicity of ammonia versus ammonium, and the importance of "stability within a range" is starting to yield some results. I firmly believe that the next few years will bring about significant change-and even breakthroughs- in the way we as a hobby manage, care for, and spawn fishes which have long been though problematic and difficult because of their specialized low-pH habitats.

It's as much about accepting a different way of thinking as it is about actually learning what's going on and attempting to replicate the function of these unique habitats.  


Mental shifts.

It's always been there for us to examine...These wild habitats. We've just been approaching replicating them with a jaded mindset. Now, we're looking at them for what they are, the benefits they provide our fishes, and just how to replicate them properly in the aquarium. And that is a HUGE leap that is happening right now...with YOU! 

Now, let me burst one final "bubble" before I call it a day here.

We hear everyone talk about "imparting tannins" into our aquarium water by using all sorts of botanicals and such. Cool...and sort of vague. 

I think that we need to be realistic with our expectations about what information we can glean from our experiments.

First off, there is currently no practical and easy "off the shelf" way, short of some pretty intense scientific testing on individual specimens of various botanicals- to know exactly how much of what color-producing and pH-reducing tannins, humic substances, etc. are bound up in the tissues of a given botanical item.

I mean, I am sure there is a legitimate way to test batches of leaves and botanicals of a specific size, for example, and come up with an average quantity (in what measure, I wouldn't be certain) of how much of "what" compounds are present.

There are ways to test for concentrations of tannin in water.

For example, the "Stiasny method", in which "a 100 mg of sample tannins are dissolved in 10 ml distilled water. 1 ml of 10M HCl and 2 ml of 37% formaldehyde are added and the mixture heated under reflux for 30 min. The reaction mixture is filtered while hot through a sintered glass filter. The precipitate is washed with hot water (5x 10 ml) and dried over CaCl2. The yield of tannin is expressed as a percentage of the weight of the starting material." Straightforward for a scientist in a lab, exceedingly difficult for the average hobbyist. 

And what are you starting the test with?

"Sample tannins" means what, in our context? Sounds discouraging, at first. Now, the good news is that there are actually test kits out there to do it. Hach, for example, makes a Tannin/Lignin test kit! And I think that will be a good starting point for many of those interested in finding out just what's going on in their aquarium.

Knowing that you have a 20 US-gallon tank filled with RO/DI water, a non-buffering substrate, and "12 Magnolia leaves, 12 Catappa leaves of 3"-4", 12 Coco Curls of about 4" in size, and 20 small Alder cones"- or whatever, yielding a tannin reading of 15 mg/l of tannic acid in the water (or whatever) will at least help establish some sort of very crude, yet aquarium-relatable guidelines.

And we need a reference- a baseline comparison to natural waters, like the Rio Negro, Atabapo, etc. for these numbers to have any real meaning, IMHO. Sure, I have studied the water chemistry composition of some major blackwater rivers based on work done in scholarly research, and much of this data is based on things we could test for in the aquarium (like TDS, pH, dissolved metals, conductivity, etc.), but something like "fulvic acid expressed as mg/l" is not something we've seen.

Now, if some of my friends and colleagues who travel to regions like the Amazon and other blackwater habitats invest in one of these $160 tannin test kits, run some samples and record tests from various sites and at different times of the year, etc. we could likely at least have a baseline for the concentrations of tannins in natural water- another target we can shoot for when trying to replicate natural conditions!

Of course, even knowing that, there are problems.

First off, just knowing "how much tannins" are in a sample of natural water, although helpful, is simply a starting point. And if we did have numbers of how much of this stuff is bound up in the tissues of the various leaves, pods, etc., -while interesting to know- it's really not all that useful when we really don't have a guideline as to how much of what specific compound or compounds are needed to create the specific effects we are looking for in our aquariums!

And of course, even knowing that- would this be based on how much of _______ you need to achieve a pH reduction, or tannin/humic substance ppm of _______ in a given sample of RO/DI water with a starting pH, TDS, and KH of...what?

And there are hundreds of tannins. Which ones are present in natural blackwater ecosystems and can be introduced into aquariums by adding botanicals? 

Damn. Not easy, huh?

Oh, and being natural items, wouldn't the levels of these compounds within the leaf or seed pod tissues themselves vary from batch to batch, season to season, and be affected by preparation, age of the materials, how they are stored, etc. etc., etc?


Vague. And challenging.

We can't fool ourselves; it's still early days in our understanding of this stuff. A grand experiment. I'm focusing a lot more on geology and aquairum substrates lately to help facilitate more "auntehtic" blackwater conditions than I am on botanicals and leaves, because that's how it works in Nature. We can't delude ourselves here. There is much to learn still.

So, if I've made any "argument" here, it's that this stuff is every bit as much of an "art"- in terms of aquarium keeping- as it is a "science." We will, at least for the foreseeable future, have to use the data we have available and formulate a "best guess" as to how much of what can give us some of the impacts we are interested in for our aquariums.

We as hobbyists and vendors simply can't authoritatively make blanket statements like, "You need to use "X" catappa leaves per gallon in order to recreate Rio Negro-like conditions in your aquarium!"  That's complete bullshit. When we use that kind of marketing hyperbole, we really are sort of shooting in the dark, and doing a great disservice to the hobby. We can simply admit that we need to observe, experiment, and celebrate the good results we achieve.

And that's certainly nothing to be discouraged about!

We, as a community, are getting deeper into the functional aspects of blackwater, botanical-style (😂) aquariums than ever before. More light is being shed on what's going on in both our aquariums and in the natural habitats we desire to replicate. We are learning more every day about how the presence of tannins and humic substances in our aquariums is affecting the health, longevity, and spawning behaviors of our blackwater fishes.

We're learning about the challenges and realities of managing blackwater systems over the long term- understanding the good, the bad, and the dangerous possibilities that are present when we experiment with these ideas.

Like everything else, just contemplating these things leads to more questions than answers, but it shows you how much more there is for us as hobbyists to learn and understand, particularly from the wild habitats. Watching our fishes and observing OUR aquariums creates unique opportunities to break away from the dangerous "groupthink" that has, in my opinion, held the hobby back in recent years.

Keeping an open mind and gently questioning "why" stuff is in our hobby will help us move beyond any previous restrains we have had.



It's an approach. A methodology. An experiment.

And it does result in some cool-looking tanks...

But definitely not a "style" in the typical sense. 

So, yeah, the word "style" is my cross to bear. Sorry about that. I'll do my best to stop using that...😆

Or, maybe not?

Yeah...Someone forwarded the definition of the word "style" as defined by Merriam-Webster:

"...a particular manner or technique by which something is done, created, or performed."

So, we don't necessarily have HAVE to lose the term "style"- we just have to think about it in a different manner. Words do matter, don't they?

Clean ending to a long discussion, huh?

That works for me.

Stay thoughtful. Stay curious. Stay resourceful. Stay patient...

And Stay Wet.

Scott Fellman

Tannin Aquatics 

Scott Fellman
Scott Fellman


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