July 13, 2020


Transitioning to "The Tint"...slowly!

It's pretty incredible to see the explosion in interest in botanical-style aquariums in the last several months. To call this stuff a "trend" is simply to sell this stuff too short. Nature abhors trends (and so do I, btw...), and the idea of using botanical materials in our aquariums is actually an extremely natural process. 

Yet, it's a lot different than what we're used to, right?

I realize that a lot of newcomers to our "side of the fence" are simply not sure if this stuff is for them. Many are drawn to the overall aesthetic, but are still put off by the idea of stuff decomposing in their aquariums; about fungal growths, biofilms, and detritus. These are things which go against the grain of everything that we as aquarists have been indoctrinated to believe.

And I think that one of the most important themes we need to continually revisit is what we've called the "mental shift" that we as hobbyists must make when working with a botanical-style blackwater aquarium.

Now, it sounds a bit, well- "dramatic"- but we've all come to realize that botanical-style aquariums have a different "operating system" (literally and figuratively) than pretty much any other type of aquatic system you'd keep. Not that there is some big "mystery" or "secret" to keeping one...Like any aquarium, you simply need to understand, appreciate, and yes- enjoy- the characteristics, phases, and nuances of this type of system.

Most immediately obvious...is color of the water.

In many botanical-style aquariums, the water sports a significant tint. It's just something that you as a newcomer to this world have to really fundamentally get used to. Now, sure, you can use botanicals in the aquarium and NOT have a 'blackwater"-like environment. You could certainly utilize activated carbon or other chemical filtration media to remove the water-tinting tannins from the aquarium while still retaining much of the beneficial humic substances, but for most of us, "brown" is a foregone conclusion.

It's what brought a lot of us to "the dark side" in the first place!

We're totally fine with it.

That being said, there is a certain "look" to the water in a blackwater aquarium which goes beyond the color. It's a sort of "patina" if you will, or a subtle variation in the way light plays upon the surface. You compare your blackwater tank to a "white water" system, and it becomes immediately obvious that there is a radical difference!

Water aesthetics aside, perhaps the toughest part of the "mental shift" for many is the understanding that botanical materials break down in the water column as they impart tannins and other substances into the environment. The well-manicured aquascape you might have conceived will be continuously reshaped by Nature as the leaves, seed pods, and other botanical materials are broken down by bacterial and fungal action.

To many, this is a huge and remarkable departure, aestehtic-wise, from the more controlled, high-concept planted "Nature Aquarium" which has been extolled for much of the past two decades. On the other hand, the transient nature of the botanicals is the very embodiment of Takashi Amano's Japanese-garden-derived appreciation for "wabi-sabi", or the acceptance of the beauty of a state of transience and imperfection.

Don't believe me? Look that shit up.

This is huge.

And then, there are the fungal growths and biofilms...

Ahh, biofilms...Yes, those lovely coatings of bacterial material that begin to appear some time after your botanicals have been submerged" for a time. The appearance of biofilms is a sort of "stage", or even a "right of passage" if you will, which almost every botanical-style aquarium goes through. And yeah, they're present throughout the functional life of these aquariums.

And, we tell our community over and over that this is a completely natural normal occurrence; bacteria and other microorganisms taking advantage of a perfect substrate upon which to grow and reproduce, just like in Nature. Freshly added botanicals offer a "mother load"of organic material  and surface area for these biofilms to propagate upon, and that's occasionally what happens - just like in Nature.  


Their presence "waxes and wanes" to a certain extent- the product of a botanical bioload. Yet they're always there, as they are in natural habitats. And making the effort to understand, and even appreciate their appearance as a sign that your aquarium is functioning as Nature intended is the biggest step in achieving what can only be called "aquatic enlightenment." 

The realization that Nature is not the pristine, orderly environment that we have conjured up in our stylized aquariums and global aquascaping contests is perhaps the most difficult thing for the aspiring "tinter" to grasp.

We've been indoctrinated for so long to think that this is the way Nature is, and that the definition of a successful, well-conceived, or "healthy and clean" system is one that consists of perfectly symmetrical/intentionally-placed/trimmed plants, pearly-white sand, and impeccably clean driftwood. Of course, the reality is that this is just one aesthetic, and that Nature rarely has such circumstances combining in the same place.

Rather, it's a world of biofilms, patinas of algae, randomly distributed botanical debris, scattered rocks and wood tangles, deposited by currents, rain, and even the fishes themselves, settling into positions that typically defy the "Golden Ratio" and other human-created constructs.

I know that much love in modern aquascaping is given to things like "surgical cleanliness", manicured plants, carefully symmetrical rockwork, proportion, negative space, etc. Many of the most breathtaking contest 'scapes adeptly embrace this concept.

That's awesome. It's all well and good...

Nature, other hand, couldn't give a flying f-ck about that.

And neither should you. 


Yeah. It's true, though.

Tough love, there!

NEWS FLASH: What we proffer-our interpretation of Nature- is not everyone's idea of a dreamy aquarium.

Frankly, it puts off some people. It scares the living shit out of others. And many just don't understand. They can't get past brown, soupy water, decomposition, and all of the good stuff that goes with it. IMHO, they've been sort of "programmed" by the world of aquascapoing contests that perfectly clean sand, bright lighting, rocks you could eat off of, and wood that, on day 45,  looks as sterile as they day it was submerged are the ONLY way to go. Oh, wait...Don't those guys usually break down their tanks by day 45?😆 Maybe it's day 30....

("C'mon, Fellman, THAT was just mean!")

It's okay. I get it. We all get it.

That's the mental shift you have to make if you're going to play with botanical-style aquariums in their purest sense.

So, how do you transition a botanical-style aquarium? It starts with a few questions:

The obvious questions we need to ask ourselves when commencing such a change are, "Do the fishes which I keep come from this type of environment in Nature?" and "Am I willing to take the time to do it slowly?"The answer to the first question is pretty obvious- and it's almost sort of insulting that I'd even mention it...but "due diligence", ya' know...

My personal recommendation is to start with relatively small quantities of materials, usually leaves, and then work in the more durable botanicals like seed pods and such. I guess my thought process is that materials such as leaves tend to break down more quickly, imparting their humic acids and tannins into the water at a corresponding pace.

And of course, after your initial additions, you should measure pH again, to see if there has been any impact. A lot of hobbyists are into checking TDS as well...We've beaten up that subject quite a bit in past blogs here, and it's discussed a lot by hobbyists, so it's something you might want to research. 

Obviously, the question here is "how much stuff do I start with?" And of course, my answer is...I have no idea. Yeah, what a shocker, right? I realize that's the least satisfying, possibly least helpful answer I could give to this question. Or is it? I mean, taking into account all of the possible variables, ranging from the type of water your starting with, to what kind of substrate material you're using, it would be a shot in the dark, at best.

My advice is to start with conservatively small quantities of stuff...like, maybe a half a dozen leaves for every 15 US gallons (56.78L) of water. You might not even notice any difference..or you might see a .2 reduction in pH...You have to test.

I recommend a digital pH meter for best accuracy.

I would make it a habit to add the same amount of materials (leaves initially, and pods if you want to mix 'em in on subsequent additions) at a regular interval. Say, every 4 or 5 days. Test again. See where you're at. I would tend to shoot for not reducing your pH by more than .5 per week. That's me of course...your fishes' tolerance and your personal comfort level with doing so is your call. And it's really a matter of repeating this process until you hit your desired range.

Notice I said "range" and not "target pH" or whatever?

And remember- as we've said a million times here: Botanicals can not soften hard water. Their influence on pH is significantly limited in water with high carbonate hardness.

We receive a lot of questions about utilizing chemical filtration media while using botanicals, and again, there is no "right or wrong" here. I will tell you from my personal experience that I like to use filtration materials like Seachem "Renew", small amounts of activated carbon ("Seriously, Fellman? Activated carbon?" Yes, really.), and Poly Filter on a full-time basis in my systems.

The reality is that organic scavenger resins, carbons, and materials like "Renew" might be indiscriminate in their removal of stuff like humic substances, tannins, and other organic compounds released by the botanicals, but they also tend to moderate things you don't want, like ammonia and "miscellaneous" organics (how's that for a "cop out" on my part...falling back on "generics!").

We toss a lot of  botanical materials (ie; "bioload") into our aquairums, all of which break down and require a bacterial population to "process" it. Why not have some chemical filtration as an "insurance policy" to remove some potential excess organics and such which will place a substantial burden on the bacterial population?

Yeah, they might remove some of the visual tint, but they will remove a lot less of it if you don't use the recommended "dose" per gallon. And frankly, I've never done a serious test to see exactly how much of what various chemical filtration media actually remove from the water. Being honest here...I'll bet not too many of you have, either, right?

So, we're kind of relying on the manufacturer's instructions and good old observation. Don't worry about the "tint" these materials will remove if used in moderation. Trust me, the water in most of my tanks is pretty damn dark, despite full-time utilization of these media! 

If you're getting a sort of feeling that this is hardly a scientific, highly-choreographed, one-size-fits-all process....you're totally right. It's really a matter of (as the great hobbyist/author John Tullock once wrote) "Test and tweak." In other words, see what the hell is going on before making adjustments. Logical and time-tested aquarium procedure for ANY type of tank! 

Now, the interesting thing that I've always found with my botanical-style, blackwater aquariums is that they tend to find their own "equilibrium" of sorts- a stable "operating range" that, once you find yourself doing the same procedures (i.e.; regular, consistent water exchanges, additions of botanicals, and media replacement, etc.) at regular intervals, tends to remain highly consistent as long as you keep them up.

I've talked repeatedly about the (IMHO mostly unwarranted) fears people have about precipitous pH "drops" and "crashes" and such, and I believe that most or all of these things are mitigated by consistency, patience, taking small steps, testing regularly, documenting and repeating them.

I've said it before an I will repeat it once again: I believe that pretty much every one of the "anomalous" pH "crashes"/disasters I've heard of in regards to blackwater, botanical-style tanks has been directly attributable to "operator error"- i.e.; failing to be consistent, diligent, and conservative. Tanks simply don't "crash" by themselves, in my experience.

They fail as a result of something we did or did not do: Failure to slow down. Failure to measure. Failure to observe or continue to follow procedures that have been giving us consistently good results. In my experience, tanks will typically show "signs", develop trends, and demonstrate the manifestations of "issues" gradually...if you're attuned to them.

Botanical-style blackwater aquariums are not "set and forget" systems, exactly like reef aquariums, planted "high tech" tanks, Mbuna systems, Discus tanks, etc. You need to observe and "pivot" as situations dictate. A sort of "yin and yang", if you will, between pushing the limits and playing it safe... And you have to ask yourself if this type of "active tank management" lifestyle is for you! 

Failure to move thoughtfully, slowly, and deliberately, testing and tweaking along the way, along with time-tested, common sense application of aquarium management technique can result in you killing every fish in your aquarium. 

That's reality.

So, don't be stupid or lazy and you'll be fine.

Okay, you're getting that idea!

The second question-the one about "taking the time to do it slowly"-is to me- more interesting..in fact, it's, as we say here in America- "The whole ball game.."(they probably say that in every country, too, but hey...).

Patience. Observation. Time.

Essential "ingredients" in the botanical-style blackwater aquarium game.

One fact:

It goes without saying that, if you've been keeping your fishes (even ones which come from blackwater conditions in Nature) in harder, more alkaline water, there will need to be a gradual transition to this type of environment. It goes without saying that rapid environmental changes are potentially harmful to many fishes. 

Now, in the bigger picture, I am of the opinion that even, for example, Tetras or other fishes that may have been bred commercially in "tap water" conditions (not necessarily soft and acidic) for the past few decades still could benefit from being "repatriated" into more natural conditions.

However, you're still putting them through an environmental change, and this requires time.

Where do you begin? 

Well, you start by seeing where you are. "Getting your bearings", so to speak.

I'd start by doing a sort of "baseline assessment" of the pH and alkalinity of my water. Digital meters are a great investment that will make accurate monitoring of your water very easy and economical. You should also give some thought about what your target pH/alkalnity are. If you're using tap water with a pH of 8.2 and considerable carbonate hardness, for example, you need to consider how you might bring these measurements down.

And you should, in my opinion, be willing to make the "infrastructure investment" (pricy though it may be) in a reverse osmosis/dioinization unit...or at least, finding a source of good, consistent RO/DI water (many fish stores will sell you RO/DI by the gallon/litre!). The rationale here is that it's far, far easier to reduce the pH in water with little or no carbonate hardness...it's more "malleable"- a better "canvas" upon which to work.

If you aren't using RO/DI water in your current setup, you can even start gradually mixing some in (without adjusting it or adding anything) with your regular water exchanges. Arguably, this may help to gradually lower the carbonate hardness and pH. Yet, it's going to take a long time. Ultimately, the idea is to replace all of the water in the tank with RO/DI. Patience is essential. Slow steps. If you can get your water to around neutral (7.0), that's a great "stepping off point" for modifications to lower pH levels.

Oh, there are other considerations- like substrate. If you're using a substrate which has considerable "buffering" capability, than it's likely that you'll either need to replace it, or accept the fact that you will likely not achieve "soft, acidic" conditions.

Now, speaking of pH- I wouldn't "shoot for the stars" and try to get to 5.5 or something really low right out of the blocks. For that matter, I wouldn't obsess over ANY specific "target number", really...Rather, I'd try to find a tight range that you could easily maintain. With the understanding that you need to do this over a period of weeks- even months...I'd shoot for a modest pH level of like 6.7-6.5 as your target range...Get a feel or operating a tank under these conditions and maintaining them consistently. 

Once you've got a sort of "handle" on the pH and alkalinity, and have gotten them "in range", you can begin the (slow) process of "fine tuning" your habitat. Now, you might be (as I often am) surprised to find that botanicals and leaves, while impactful somewhat on pH, will drop levels much more slowly, and to a lesser extent than you might think. And if you have harder, alkaline water, the impact will be even more minimal or even undetectable.

As we've mentioned many times, the impact on carbonate hardness from botanicals and leaves is essentially nothing. They won't accomplish "softening" of water- a myth that's been erroneously ascribed to them for decades. A study of basic water chemistry will bury this myth once and for all. 

You simply need to utilize other methods to reduce KH (like the aforementioned use of RO/DI water) before even starting to add the botanicals and leaves, if your goal is to reduce pH in the system with them.

The other, probably insultingly obvious thing to be aware of is that, even if the water looks dark brown, it's not necessarily 6.3 and zero KH. I mean, tannins will stain water in the absence of chemical filtration media to remove them. They may not significantly impact the pH, as mentioned above, but you'll get that "visual tint." 

And I know many hobbyists who are perfectly happy with that.

And let's talk about the idea of tannins and humic substances for a second. We know that they are released into the water as a result of steeping botanical materials. And yes, there are commercial test kits to measure tannin levels (usually used in winemaking and such). They will give mg/l readings, which are, unfortunately, of no real use to hobbyists at the present time.


Because we simply don't have baseline information which hobbyists can interpret about tannin levels and/or humic substances in natural habitats, nor an analysis of which of the hundreds and hundreds of tannins and humic substances are typically found in most blackwater habitats.

At this time, we simply have to go with the understanding that these compounds ARE found in natural blackwater aquatic habitats at varying concentrations and combinations. Until further research is completed, interpreted and analyzed, we unfortunately simply have to "trust" this stuff! Yet another reason to study the wild aquatic habitats of the world even more closely.

I am also not aware of any studies done on the health impact to tropical fishes of tannins and humic substances in harder, alkaline environments versus soft, acidic ones, so it's sort of an open topic, really. 

Not exactly 100% definitive, completely confidence-building stuff, right? I mean, we know that these things are there. We know they're important, but we don't know a whole lot more at this point- at least, not hobby-wise. 

And that's not only the challenge- but (in my opinion) the appeal- of this aquarium specialty. We all have an opportunity to contribute to the state of the art. To increase our body of knowledge of how these systems operate. To unlock the manifold benefits- and potential pitfalls- of botanical-style aquarium "practice."

It's not for everyone. Not everyone likes the look. Not everyone likes the work and effort required. And the lack of a "recipe" or complete "step-by-step-guaranteed-to-work-every-time" thing is daunting to some.

We're still at the phase when what we do is as much of an "art" as it is a "science." Now, that's not a bad thing, mind you. Just something we need to take into account as we persue our work. 

We at Tannin have begun developing a whole suite of specialized products designed to compliment the botanical-style aquarium and add some degree of predictability to the game...Yet there is so much more to do.

There is no "dial-a-river" solution just yet...And frankly, I'm kind of glad. The fun is in the experimentation. The journey. The discovery...

I suppose that this piece probably didn't answer all of your questions. Rather, I'll bet that it opened up quite a few more, spurring you to do more research before starting a blackwater, botanical-style aquarium...That's never a bad thing! 

Stay excited. Stay careful. Stay experimental. Stay diligent. Stay skeptical. Stay hopeful. Stay creative. Stay enthralled ..

And Stay Wet.

Scott Fellman

Tannin Aquatics 

July 12, 2020


Hahnel knew it...

The history of aquarium keeping is an intimate mix of exotic fishes, equally exotic locales, interesting practices, and amazing people. If you go back into the history of our hobby, you're likely to encounter a few names that transcend both time snd geography: Axelrod, Baensch, LaCorte, Fenner, and a guy from New York (via Germany) named Paul Hahnel. 

Often called the "Father of the Fancy Guppy", Hahnel is considered one of the giants of the aquarium hobby, having pioneered the technique and disciplines which helped make the fancy guppy one of the world's most popular and beautiful fishes.

Hahnel and his contemporaries were pioneers, but they were not scientists in the traditional sense. Rather, hobbyists such as Hahnel applied careful observation, discipline, patience, and a healthy dose of common sense into their technique. This is a set of characteristics which has not only distinguished great hobbyists from "average" hobbyists for generations, it helps advance the hobby.

They shared this knowledge freely.

Some of my fave quotes from this guppy legend included stuff like, "Just feed good live and dried food when you pass by your tank from the left, and siphon out 10% of the water when you pass from the right.."

Obviously, this is sort of metaphoric, but the idea rings clear through the decades: Feed your fishes well, and change the water on a regular basis. In other words, be consistent in both husbandry and maintenance. Observe.

And it's really that simple. It's about two key factors in aquarium keeping. This idea of keeping our aquarium water as low in metabolic compounds as possible, while simultaneously feeding our fishes with the most nutritious foods possible as often as possible.

Funny, guppies and guppy breeders sort of formed a "through line" in my fish-keeping pedigree...

For me, growing up in a house full of guppy tanks (My dad was a big fancy guppy fan), the names that came up often were the legendary guppy breeders of the day- Paul Hahnel. His books were all over my dad's fish library, so it was only natural that I'd end up reading them as a kid.

And of course, there was the well-worn copy of the William T. Innes classic, "Exotic Aquarium Fishes"- the book that I literally read a thousand times...cover to cover. Memorized every species name, could quote some of his charming passages about their care, and about stuff as esoteric and "fish-geek-precious" as his discussions on waking up very early in the morning to net Daphnia for fishes off of local ponds. I can still quote the passage that was the "mantra" for the working fish geek:

"Future generations may smile at our working hours, but this allows the tropical fish enthusiast to be at his salaried position by eight..."

I remember haunting the local pond, collecting fairy shrimp and mosquito larvae (which endeared me to my mom to no end) before school, inspired largely by that passage!

In fact, Innes' book had a great picture of one of my all-time favorite fishes, Crenuchus spilurus, the "Sailfin Characin", which I finally acquired after a lifetime in the hobby. It was a huge event for me...

My copies of these books were so beaten up that you could barely open them without pages falling out. I read 'em over and over and over...

These books, written decades before I was even born, and the lessons of people like Hahnel, Innes, and LaCorte, were still the backbone of my "fishy education." And the interesting thing about these old books- and much of the advice preferred in them- is that they stand the test of time. Most of this stuff is fundamental husbandry and common-sense concepts related to the selection, care, and breeding of fishes.

Sure, some of the names have changed, and some things have become more common, like breeding Discus, which in Innes' 1939 edition, was being hailed as one of the greatest tropical fish achievements in history..which, when you think of it in the context of the era...was true.

And then, there was the great Rosario La Corte- one of my favorite all time fish hobbyists. His little paperback book, "Enjoy The Tetras", is pretty much the "vector" for my lifelong love of these fishes. 

He bred hundreds of species of fishes, wrote about them tirelessly in books and magazines, and freely shared his trials and tribulations in grand fish-geek style. I recall in 2012, I was in the New York area and was invited to a meeting of the Long Island Killifish Association, where he was there! At the time, I was pretty much at the top of my "Reef game", fish-geek-star wise, a featured speaker at every major reef conference, clubs worldwide, and an author in online media...Yet, mindful of my pedigree, I was absolutely like a 13-year old girl about to meet her fave TikTok star!

I remember how excited and nervous I was to meet the legend in the flesh.

And you know what? He didn't let me down. He was one of the nicest, most humble fish guys I ever met, and took the time to talk with me about who-knows-what (I think I must have simply repeated "I've read all of your books-like 20 times..." over and over again.), and lived up to his legendary status!

And of course, no other hobbyist, past or present, has ever had the amazing and complete influence on me that my father did. He literally started me with a bowl of fishes when I was 3, and I haven't looked back since. He passed away a few years back, but he influences me every single day.

My dad knew something that was pretty remarkable: If you have a passion, share it with your children. Teach them what you know, nurture their dreams, answer their questions, and encourage them in every way.

Give your son or daughter their first fishbowl, nano-tank, baby guppies. Allow them to feel the excitement when they add that new Tetra, find that cool Angelfish they've been looking for, pick kill eggs from a spawning mop for the first time, or create that perfect aquascape. 

Embrace their geeky enthusiasm. 

And that's what parents who are fish geeks do. It's what fish geeks who just happen to NOT be parents do. It's what fish geeks in general do!

In every field of endeavor, we have our influencers, thought leaders, and yes- legends. People who, through action and thought, have positively influenced the culture and technique of what we do. The tropical fish hobby is no different- except that at the end of the day, most of the key influencers and even the "legends" are gracious, humble, and just good-old fish geeks, like you and me. They have working fish rooms, spill water on the floor, and make all sorts of mistakes...and laugh about them!

And they all carry with them the knowledge borne of effort, enthusiasmm, hard work, and patience. There are no real shortcuts in this hobby- no ways to "beat the system"

There words and lessons resonate across time; transcending eras and generations- and ring as true as they did when they were first written...Much of it simple, concise, and easy to accept.

How funny that the most simple advice I've ever received has guided my aquatic passions far more than some of the complex directives I've been given by well-intentioned aquarists over the years.

Or is it?

We all can learn from the body of knowledge accumulate in the decades before we ever had an aquarium. These are ideas- a culture- which guides everything we do. Sharing our experiences, reaching out to fellow hobbyists, and just talking- has never been more important than it is now. Keep no secrets.

So I guess my one "plea" to all of you crazy-cool fish expert/"obsessionistas" would be to reach out across the aisle- to poke your head over the fence- and share some of your amazing expertise and experience within your specialty to others working in different areas. This will ensure not only that your hard-won information and ideas are not confined only to your specific area of obsession- it will perhaps foster breakthroughs in other hobby specialty groups.

And some of those breakthroughs might just be the key to the long-term well-being of the hobby as a whole, and to sharing, educating about, propagating, and protecting the fishes- and habitats of the world -which so desperately need our attention.


It's what Hahnel knew. It's what every hobbyists knows.

Stay collaborative. Stay open-minded. Stay passionate. Stay generous...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


July 10, 2020


The mess we make.

As you know by now, I am pretty much near-obsessed with the idea of allowing a botanical-style aquarium to "evolve" with little interference on the part of the aquarist. With botanical-style aquariums, I personally believe that they can better handle evolving on their own more so than many typical systems...Not that I'd want to just "let a tank go", mind you...

I'm a fairly diligent/borderline obsessive maintenance guy. I love my weekly water exchanges. However, I think it's very important to understand the reason why we create aquariums like this. What is the goal? What are we trying to accomplish? If we make an effort to understand the way the natural habitats we are enamored with function, it becomes way easier to manage them in a more confident manner.

Hobbyists unfamiliar with our processes and ideas will call this a mess.

We call it "natural."

I mean, when you think about it, the natural, botanical-style blackwater aquarium is sort of set up to replicate a habitat where all of this stuff is taking place already. Leaves, seed pods, etc. are more-or-less ephemeral in nature, and are constantly breaking down in these environments. Decomposition, accumulation of epiphytic growth, and colonization of various life forms is continuous.

Exactly what happens in these habitats.

As we've discussed before, an aquarium has a “cadence” of its own, which we can set up- but we must let Nature dictate the timing and sequencing. It starts with an empty tank. Then, the lush fragrance exuded by crisp botanicals during preparation. The excitement of the initial “placement" of the botanicals within the tank. The gradual “tinting” of the aquarium water. The softening of the botanicals. The gradual development of biofilms and algae “patinas.” Perhaps, even a bit of cloudiness from time to time because of microbial growth.

Ultimately, there's the decomposition.

It's part of the cycle of life in Nature- and in our aquariums.

All part of a process which can’t be “hacked” or rushed. We can change some of the physical aspects of our tanks (equipment, hardscape, etc.), but Mother Nature is in control.

She "calls the shots" here.

And I think that's perhaps the most important lesson that we can learn from our aquariums. As aquarists, we can do a lot- we can change the equipment, correct initial mistakes or shortcomings the system might have had from the beginning.

We set the stage, so to speak.

However, in the end..it's Nature which does most of the real "heavy lifting" here. Nature rewards us for our good decisions, scolds us for our bad ones, and provides "cues" on what future decisions we need to make. And Nature does it all indifferently...without judgement.

It reacts positively or negatively to our attempts to control it. Both in the wild, and in the confines of an aquarium.

Yes, I know an aquarium is not "Nature"- but it does function in accordance with Nature's laws, regardless of what we want, right? And it is an ecosystem to the organisms which inhabit it.

One of the things that we've seen be more accepted in the hobby over the past few years is a trend towards more "realistic" aquariums. Not just systems which look like natural environments; rather, systems which are modeled as much after the function of them as the aesthetics.

"Functional aesthetics."

I think this is where Tannin Aquatics falls, if you had to nail us down into one specific "stylistic/philosphical approach" to aquariums.

The "space between", so to speak. Sort of straddling multiple approaches, with Nature as the ultimate "critic."

A less rigidly aesthetically-controlled, less "high-concept" approach to setting the stage for...Nature- to do what she's done for eons without doing as much to "help it along." Rather, the mindset here is to allow nature to take it's course, and to embrace the breakdown of materials, the biofilms, the decay...and rejoice in the ever-changing aesthetic and functional aspects of a natural aquatic system- "warts and all" -and how they can positively affect our fishes.

So, that's the whole philosophy behind the botanical-style aquarium and how it functions. How do we best facilitate smooth operation of our systems to accommodate Nature into the process?

We start by accepting the idea of decomposing materials accumulating in our systems. We understand that they act, to a certain extent, as "fuel" for the micro and macrofauna which reside in the aquarium, and that they perform this function as long as they are present in the system.

Sure, if it just bothers the shit out of you, you could remove some of it from time to time. However, I have long been one the belief that if you decide to let the botanicals remain in your aquarium to break down and decompose completely, that you shouldn't change course by suddenly removing the material all at once. 

Slow, steady moves are the way.

Our aquariums, much like the wild habitats we strive to replicate, are constantly evolving, accumulating new materials, and creating new physical habitats for fishes to forage among. New food sources and chemical/energy inputs are important to the biological diversity and continuity of the flooded forests and streams of the tropics, and they play a similar role in our aquariums.

We add leaves and botanicals periodically, not just for an aesthetic "refresh", but for a "re-charge" of the biome within our tanks. This is a fascinating spect of the botanical style aquarium. It facilitates the cycle of growth, nutrient accumulation, and decomposition. It becomes not only part of our practice, but it's part of the "system" we are trying to facilitate.

If you look at an aquarium as you would a garden- an organic, living, evolving, growingentity- then the need to see the thing "finished" becomes much less important. Suddenly, much like a "road trip", the destination becomes less important than the journey. It's about the experiences gleaned along the way. Enjoyment of the developments, the process. In the botanical-style aquarium, it's truly about a dynamic and ever-changing system.

Every stage holds fascination. 

And, once stuff starts "softening" or breaking down, it doesn't mean that your job is done, or that you're just an observer from that point on. Nope. It means that you're now in a cool phase of "actively managing" (and by "managing", I am emphasizing observation more than "intervening!") the aquarium.

Sure, when you embrace this mindset, you're making minor "tweaks" as necessary to keep the aquarium healthy and moving in the direction-aesthetically, functionally, and otherwise- that you want it to. Yet, at some point early in the process- you find yourself just letting go and allowing the tank to do what Nature intends it to do on it's evolutionary path...

A lot of people may disagree, but I personally feel that THIS phase is the most exciting and rewarding part of the whole process!  And perhaps- one of the most natural...if we allow it to be.

And allowing the aquarium to sort of forge its own path, and to process the materials in the closed ecosystem allows Nature to do her thing...

Nature can control. Nature can stabilize. Nature can admonish us...However, Nature can also provide.

We've talked a lot about allochthonous input- food which comes from outside the aquatic environment- such as insects, fruit, seeds, etc. You know, stuff which literally falls from the trees!

However, there is also a significant amount of food which our fishes can obtain which occurs within the aquatic habitat itself. 

This is something that we, as lovers of the botanical-style aquarium, are well-suited to embrace. And of course, I'm utterly fascinated by the concept of food production within our botanical-style aquariums! Yes, food production. If you really observe your tank closely- and I'm sure that you do- you'll see your fishes foraging on the botanicals...picking off something.

I've noticed, during times when I've traveled extensively and haven't been around to feed my fishes, that they're not even slightly slimmer upon my return, despite not being fed for days sometimes... 

What are they eating in my absence?

Well, there are a number of interesting possibilities.

Perhaps most interesting to us blackwater/botanical-style aquarium people are epiphytes. These are organisms which grow on the surface of wood, botanicals, plants or other substrates, and derive their nutrients from the surrounding environment. They are important in the nutrient cycling and uptake in both nature and the aquarium, adding to the biodiversity, and serving as an important food source for many species of fishes.

THAT is why I think it's advisable to allow botanical materials to break down completely in the aquarium.

No real mind-blowing, world-changing tactic here...well, not on the surface, at least.

Yeah, there are those out there-short-sighted, in my opinion- who view what we do as simply making a mess...

However, if you put some thought into this as a process- a practice that is all about the 'evolving" nature of your aquarium. Something analogous to what goes on in the wild. Something that fosters biological and chemical interactions and impacts we have come to see as part of the fascination of our blackwater, botanical-style aquariums.

Stay diligent. Stay creative. Stay observant. Stay excited. Stay patient...

And Stay Wet.


Scott Fellman

Tannin Aquatics 



July 09, 2020


Digging those Geos!

One of the fun things about the aquarium hobby is that there seems to be a fish, or group of fishes, for almost every taste. Those of you who know me well are aware of the fact that I tend to favor small, relatively docile fishes, like characins- the "Teacup Poodles" of the aquarium world.

Although I'm not alone in my love for the little guys, there are plenty of hobbyists who love larger, more aggressive, more "destructive" fishes. Well, I may not favor those fishes in my tanks, but I do have a healthy respect and admiration for some of the more- shall we say- "hardcore" fishes...like the so-called "Eartheaters" (families Acarichthys, Biotodoma, GeophagusGuianacaraGymnogeophagus, and Satanoperca).  

Theyre party of a tribe known to taxonomists as Geophagini. This lively and diverse group contains some of the most endearing and interesting cichlids around. With a surprising number of our customers wanting to incorporate botanicals in setups with these fishes, I couldn't NOT take a little look at them in "The Tint", right? 

(Gymnogeophagus balzanii. Photo by CHUCAO, under CC BY-SA 3.0)

And of course, the name of the genus Geophagus contains the Greek root words for "earth" and "eat", as if to reinforce the popular collective name. So, in case you haven't figured it out by now...They dig in the sand to get food...oh, and they shit.

A lot.

And some are large and mean.

Of course, you probably already knew that, and I'm the last guy you really want to write one of those "Review of the Eartheaters"-type articles, so we're going to focus more on the kind of environment you'd want to set for these bad-asses, from a botanical-style aquarium perspective, of course.

And of course, it's irresponsible for me to simply generalize about all of them as a group. Not all of the Eartheaters are mean, destructive fishes. Not all are huge. However, you need to really study the attributes and behaviors of the species you're into. 

(Satanoperca leucosticta- image by Dr. David Midgely, used under CC BY-SA 2.5)

So, without getting too specific, suffice it to say that the bulk of them do fine in neutral to slightly acidic environments. Hailing from South America (Brazil, Northern Argentina, Paraguay, and Uruguay), including Amazonia, many inhabit areas with a mix of botanicals, rocks, and of course, sand or sediment.

Yes, you'll see plants in these environments, too, but not always true aquatics, so we'll focus on the botanical aspect. Besides, as you know, I'm hardly the guy you'd go to for information on plants, right? I'm sort of a botanicals, leaves, and driftwood kind of guy, myself...

So, like how would you use botanicals with these fishes?

Hailing as they do from environments that have both swift currents and sluggish water movement, you can use a mix of bigger, heavier botanicals with some of the smaller ones. Rocky, sandy, botanical-strewn bottoms are common habitats for these fishes.

You'll often see them in habitats with sandy, silty substrates and a few leaves and such scattered around. Of course, these environments are slightly turbid, not only because of the currents, but because of the digging activities of these fishes.

Many species are also found in swamps adjacent to streams or rivers, with far less water movement and more placid water flow.

One interesting thing that we should think about when housing these guys in tanks with botanicals- a fair amount of these fishes need some "roughage' in their diet- usually in the form of plant materials...However, some of the "softer" botanicals, such as leaves, coco curls, etc are often "mouthed" by these fishes, so that's something to think about when keeping them in a botanical-influenced tank.

Now, I wouldn't specifically go for a leaf litter-only tank with these guys- they'll simply move it around and create a sort of boring look. Rather, I'd go with some of the more durable, larger materials, in various sizes. The beloved Cariniana Pods  (when the damn things are back in stock from our suppliers- thanks, Covid, you piece of shit!) and "Helix Pods" are perfect "props" for these fishes, offering them an interesting and stimulating physical habitat.

Although the bulk of these fishes reach sizes which will make some of these pods useless as a hiding place after they're just a few months old, these will function as the equivalent of a dog toy!  And, the larger, more durable pods make pretty cool "props."

My preference for botanicals with fishes like this would be an abundance of the more durable stuff, in various sizes, such as Mokha Pods, or Jacaranda Pods, which have "nut-like" outer shells that can easily be moved, and are analogous to some of the botanical materials that you'd see falling into rivers and streams.

Hmm, it's that allochthonous input thing again!

And you know that I find this a fascinating behavior, right?

(A classic, Geophagus brasiliensis. Image by Cezary Porycki, used under CC BY 3.0)

Since many species do forage of fruits and other botanical materials as part of their diet, you could include some of the more "transitional" materials, like  Calotropis pods, which soften significantly after being submerged, and are a favorite of shrimp and many catfishes, too.

Damn, if I keep suggesting materials to use with your Eartheaters, this blog is simply going to end up sounding more like a sales brochure for our stuff than anything else, so I think you get the idea by now....

In summary:

You can use pretty much any of our botanicals with these unique cichlids, within reason. We receive a lot of request for "Enigma Packs" designed for these fishes. And of course, when we curate them, we try to take into account the species that the pack is intended for.  Of course, we can generalize a bit when selecting botanical materials for these guys...

The key, IMHO, is to mix more durable materials, which can hold up to the "chewing" and digging and general moving-around-the-tank activities that these guys are known to engage in throughout the day.- in with the more "transitional ones You can create a cool aquascape that is both functional and aesthetic by using a nice mix of the larger, more durable botanicals with more traditional hardscape elements like wood, etc.

To quickly summarize, these endearing fishes are surprisingly good candidates to keep with botanicals, because while many are not specifically from tinted, blackwater environments, the bulk (heh, heh) of them do come from environments which have "botanical influence" from materials that fall into their habitats from overhanging trees and such.

(Acarichthys heckelii- Image by Dr. David Midgely under CC BY-SA- 2.5)

I also think that we as hobbyists make entirely too much out of the "They make the water cloudy!" argument. I mean, sure, many of them dig. You need good circulation, filtration, and overall husbandry. But guess what? If the water is a bit turbid because sediment and sand are in the water column because of the excavation efforts of these fishes...who cares? The fish?

I don't think so.

I mean, yeah- they dig, and they'll make their aquarium environment turbid as a result. So, you compensate with good husbandry- but you need not freak out by trying every possible avenue to make the water crystal clear. I'm feeling that we place way too much emphasis on this attribute in aquarium keeping- feeling that any turbidity or color in water is somehow "problematic."

As we know by now, many habitats in Nature, including those where this trip of fishes comes from, are anything but "crystal clear."

So keep enjoying these fascinating, high-octane cichlids...and keep creating "functionally aesthetic" displays for them! Let us know if you've found that some of the botanicals seem to work better than others for these guys! 

Stay excited. Stay dedicated. Stay engaged. 

And Stay Wet.

Scott Fellman

Tannin Aquatics


July 08, 2020

1 comment

"Throwing Shade..."

One of the coolest things of having a "front row seat" to the evolution of the botanical-style aquarium "movement" is that I get to sort of function as a "learning house" for a lot of new and exciting ideas and approaches which my fellow hobbyists share with me regularly!

Sometimes, our shared progression and experience even makes me think about my own personal "rules" and directives. Pushing outwards has really helped me grow in the hobby.

Now, one of the things I've often talked about over the years here is the need for us as hobbyists to deploy patience, observation, and testing when playing with botanical materials in our aquariums. I've eschewed, even vilified "hacks" and "shortcuts"...I felt (and continue to feel, really), that trying to circumvent natural processes in order to arrive at some "destination" faster is an invitation to potential problems over the long term, and at the very least, a way to develop poor skills that will work to our detriment.

Obviously, I'm not saying that the botanical-style aquarium approach should be all drudgery and ceaseless devotion to a series of steps and guidelines issued by...someone. NO! That's even more frightening to me than the idea of "shortcuts" and "hacks!" Dogma sucks. And guess what? Ideas and practices evolve over time as we learn more about what we're doing and accumulate more experience. And that often makes me re-visit ideas which I might have formerly looked at in a more negative way.

Yeah, imagine that? Even crochety old me re-visiting ideas I've formerly "poo-pooed."

One of the questions we receive a lot is, "Can I use the water which I prepare botanicals as a sort of 'blackwater extract' or 'tea' to add to my aquarium?"  My answer has been, and still is the same: I don't recommend it, because in addition to the tannins and humic substances which are exuded during the prep process, you are also releasing a lot of dirt, dust, and organic pollutants which are bound up in the surface tissues of your botanicals.

My feeling is that the addition of a concentrated "brew" of the very stuff you're trying to eliminate via preparation into your aquarium is counter-productive at least, and downright detrimental to water quality at worst! Hardly worth the trade-off of losing ga small amount of the treasured tannins and humic substances, IMHO.

Yet, the questions continued. And the idea of utilizing the "tea" produced during the prep process persisted. And people asked about other stuff.

Hobbyists have for years played with other alternatives, such as Rooibos tea, which, in addition to bing kind of tasty, has been a favored "tint hack" of many hobbyists for years. Without getting into all of the boring details, Rooibos tea is derived from the Aspalathus linearis plant, also known as "Red Bush" in South Africa and other parts of the world. 

(Rooibos, Aspalathus linearis.  Image by R.Dahlgr- used under CC-BY S.A. 2.5)

It's been used by fish people for a long time as a sort of instant "blackwater extract", and has a lot going for it for this purpose, I suppose. Rooibos tea does not contain caffeine, and and has low levels of tannin compared to black or green tea. And, like catappa leaves and other botnaicals, it contains polyphenols, like flavones, flavanols, aspalathin, etc. 

Hobbyists will simply steep it in their aquariums and get the color that they want, and impart some of these substances into their tank water."Cold extraction." I mean, it's an easy process. Of course, like any other thing you add to your aquarium, it's never a bad idea to know the impact of what you're adding. 

Like using botanicals, utilizing tea bags in your aquarium requires some thinking, that's all. 

And of course, it got me thinking. I mean, tea is essentially defined as, "...a hot drink made by infusing the dried crushed leaves of the tea plant in boiling water."

I suppose that, by definition, it doesn't really differ substantially from what we are producing when we utilize botanicals in our aquariums- with the notable exceptions that we are: a) not drinking our tank water and b) allowing the botanicals themselves to impart the tannins and humic substances at their own "speed" over time (after preparation) into the water. More like a slow infusion, right? Oh, and of course, using the botanicals themselves in our tanks allows fishes and other aquatic animals to interact with them and use them for shelter and foraging, just like they do in the wild...

And yeah, I admit, I was openly critical of the idea of using Rooibos and many "extracts." 

The things that I personally dislike about using tea or so-called "blackwater extracts" are that you are simply going for an effect, without getting to embrace the functional aesthetics imparted by adding leaves, seed pods, etc. to your aquarium as part of its physical structure, and that there is no real way to determine how much you need to add to achieve______.

Obviously, the same could be said of botanicals, but we're not utilizing botanicals simply to create brown water or specific pH parameters, etc.

Yet, with tea or extracts, you sort of miss out on replicating a little slice of Nature in your aquarium. And that's a different sort of thing. And getting my head around this sort of changed my thinking just a bit.

Of course, it's fine if your goal is just to color the water, I suppose. And I understand that some people, like fish breeders who need bare bottom tanks or whatever- like to condition water without all of the "leaves and twigs and nuts" we love.

THAT suddenly registered in me!

There is ( I know, because I listen to you guys!) an entire population of aquarists who love the tint of the water, the benefits of humic substances and tannins, but simply don't like all of the decomposing materials, biofilms, etc. which accompany the addition of botanicals in aquairums.

On the other hand, if you're trying to replicate the look and function (and maybe some of the parameters) of THIS:

You won't achieve it by using THIS:

It's not "wrong" or "lazy"- it's simply a different route....for a different purpose!

And look, I understand that we are all looking for the occasional "shortcuts" and easier ways to do stuff. Life is busy. This is supposed to be fun. And I realize that none of what we proffer here at Tannin is an absolute science. It's an art at this point. There is no current way available to the hobby to test for "x" types or amounts of tannins (of which there are many hundreds) in aquariums.  I have not even found a study thus far which analyzed wild habitats (say, Amazonia) for tannin concentrations and specific types, so we have no real model to go on.

The best we can do is create a reasonable facsimile of Nature.

We have to understand that there are limitations to the impacts of botanicals, tea, wood, etc. on water chemistry. Adding liter upon liter of "extract" to your aquarium will have minimal pH impact if your water is super hard. When you're serious about trying to create more natural blackwater conditions, you really need an RO/DI unit to achieve "base water" with no carbonate hardness that's more "malleable" to environmental manipulation. Tea, twigs, leaves, extracts, "Shade"- none will do much unless you understand that.

I'm not trying to throw a wet blanket on any ideas we might have.

I'm not feeling particularly defensive about using tea or other "extracts" because I sell botanical materials for a living. It's sort of apples and oranges, really.

So I rolled up my sleeves and started to think about a better way to impart the benefits of our botanicals and leaves into aquariums in a manner which will provide some of the benefits without the associated materials in the aquarium, which breeders, planted tank enthusiasts, and other speciality hobbyists might not want or need for their purposes.

Why exclude these people from experiencing the benefits of botanicals?

Now, I realized that various types of teas and crushed catappa leaves in tea bags have been used for years by hobbyists. This is hardly a "new" or "revolutionary" idea. Like so many things we do at Tannin, my idea was to evolve the process and refine it more. To do better. To employ a different set of "ingredients." To give hobbyists a product that can deliver more consistent, more predictable results and instill a greater degree of confidence than what's previously been offered in this form factor. 

I reached out to one of my trusted botanical suppliers overseas and started the process. What we came up with, after a number of iterations was a series of carefully-formulated blends of carefully prepared, dried, and ground-up botanicals and leaves- the same ones we offer in our web site collections- which will provide specific color effects with a simple "delivery" method.

The result was a series of sachets (I mean 'tea bags" is SOOO pedestrian, right?) with the correct amount of the right ratio of our botanicals and leaves to impart predictable, consistent color effects (and, by extension, the same types of humic substances and tannins you'd expect with our "intact" botanicals) in an easy-to-use form factor.

We call the product "Shade"- and we think this is a big "upgrade" over the products of the same type which have been offered before. The cool part is that, since they're formulated from the same Tannin botanicals we've collectively been offering playing with for years, we understand the "color effects" that all of our materials can impart to the water. This gave us the ability to come up with three different "flavors", each which can give a different effect. We'll be releasing the other "flavors" in the months to come!

Our first release will impart a "classic" golden-brown color into the water. Future releases will impart a light golden color into the water, and a deep red into your tanks. 

Fun. Easy to use. Effective.

"A hack, Fellman?"


A different form factor. A variation of how we do this stuff.

"It's a hack, Fellman!"

You'll never convince me that it is...Even if it sort of IS! 😆

And we have found, through a lot of testing and trial and error, that, unlike botanicals themselves, we can sort of develop a rough (albeit superficial) "dose" for the sachets. We've found that one sachet can influence about 5 U.S. gallons of water. And yeah, I know, I typically HATE - I mean REALLY despise making such "x" number of leaves or seed pods per gallon" recommendations.  This is a bit different, of course, because of the form factor of "Shade."

Now, by "influence", I'm referring to the color. Sure, these sachets could also impact pH of the water if you use reverse osmosis/deionized water to operate your aquariums. If not, they'll simply impart some color (and likely tannins and humic substances) into the water...Not a bad thing, but don't fool yourself. You need to test the impact of "Shade" on your water chemistry to know for sure.

Although "Shade" is a carefully formulated  well-tested alternative to "dumb old tea bags", it's not a "miracle" product.  It just isn't. "Shade" won't guarantee that you'll get your wild Cardinal Tetras to spontaneously spawn on command. It won't cure fungal diseases. It WILL help you achieve the color effects you are looking for. It WILL offer many of the same potential health benefits to your aquatic animals that using our botanicals in your aquariums in their "natural" form will. Of course, even those benefits are STILL not fully understood, 100% predictable, or really all that well-defined! (C'mon, you didn't think I could guarantee THAT kind of stuff, did ya?)

It's a cool product.

Better than what's out there now, if we say so ourselves.

Yes, it's not super-duper cheap like products which consist of just crushed catappa leaves are- becuase more botanical materials, more thought, and more "R&D" went into this product! Some of you won't like it, or simply dismiss it as bullshit or whatever. I get it. Personally, I think it's going to become a very popular item; a useful vehicle for imparting our beloved tannins and humic substances into our aquariums in a very different way.

However, like everything we do with botanicals, it's still sort of "experimental" to a certain extent. Yeah, it is. Until we have the means to analyze the exact types and concentrations of tannins and humic substances in every botanical we offer, and until these are cross-correlated with the specific types and concentrations of humic substances and tannins found in the natural habitats of our fishes, this approach will remain at best, a sort of "best guess" approach to fish-keeping!

And that's okay. It's evolving. And we're all contributing to the evolution!

Like everything we offer here at Tannin, we hope that you utilize Shade in ways that are creative, inspiring, beneficial to your fishes, and above all- fun! It's not a "game-changing" product- rather, it's a strong evolutionary step towards making the idea of botanical-style aquariums more accessible to a wider variety of hobbyists.Of course it's not for everyone. However, "Shade" is an important part of our on-going mission to help "tint the world", and blur the lines between Nature and aquarium.

We look forward to sharing more with you about "Shade" in coming days.We look forward to hearing about YOUR experiences with this new product! 

Stay focused. Stay excited. Stay bold. Stay creative. Stay diligent. Stay observant...

And Stay Wet.


Scott Fellman

Tannin Aquatics 




July 07, 2020


The worlds we create...

An aquarium is not just a glass or plastic box filled with water, sand, plants, wood, leaves, seed pods, and fishes.

It's not just a disconnected, clinical, static display containing a collection of aquatic materials.

It's a microcosm.

A vibrant, dynamic, interconnected ecosystem, influenced by the materials and life forms-seen and unseen- within it, as well as the external influences which surround it. 

An aquarium features, life, death, and everything in between.

It pulses with the cycle of life, beholden only to the rules of Nature, and perhaps, to us- the human caretakers who created it.

But mainly, to Nature.

The processes of life which occur within the microcosm we create are indifferent to our desires, our plans, or our aspirations for it. Sure, as humans, we can influence the processes which occur within the aquarium- but the outcome- the result- is based solely upon Nature's response.

In the botanical-style aquarium, we embrace the randomness and unusual aesthetic which submerged terrestrial materials impart to the aquatic environment. We often do our best to establish a sense of order, proportion, and design, but the reality is that Nature, in Her infinite wisdom borne of eons of existence, takes control.

We have two choices: We can resist Nature's advances, attempt to circumvent or thwart her processes, such as decomposition, growth, or evolution.

Or, we can scrape away "unsightly" biocover on rocks and wood, remove detritus, algae, and trim our plants to look neat and orderly.

Or, we can embrace Her seemingly random, relentless march. 

We can make mental shifts, which look at stuff like the biofilms, fungal growth, decomposing leaves, and tinted water.

Mental shifts which start by accepting the look.

It's not a mystery that botanical-style blackwater aquariums simply look different. 

Now, it sounds a bit, well- "dramatic"- but we've all come to realize that this type of aquarium simply has different "operating parameters" (literally and figuratively) than pretty much any other type of system you'd keep. Not that there is some big "mystery" or "secret" to keeping one...Like any aquarium, you simply need to understand, appreciate, and yes- enjoy- the characteristics, phases, and nuances of this type of system.

The biggest parts of the "mental shift" are the understanding that botanical materials break down in the water column as they impart tannins and other substances into the environment. The well-manicured aquscape you might have conceived will be reshaped by Nature as the leaves, seed pods, and other botanical materials are broken down by bacterial and fungal action.

The realization that Nature is not the pristine, orderly environment that we have conjured up in our stylized aquariums and global aquascaping contests is perhaps the most difficult thing for the aspiring "tinter" to grasp. We've been indoctrinated for so long to think that this is the way Nature is, and that the definition of a successful, well-conceived, or "healthy and clean" system is one that consists of perfectly symmetrical/intentionally-placed/trimmed plants, pearly-white sand, and impeccably clean driftwood.

Of course, the reality is that this is just one aesthetic, and that Nature rarely has such circumstances combining in the same place. Rather, it's a world of biofilms, patinas of algae, randomly distributed botanical debris, scattered rocks and wood tangles, deposited by currents, rain, and even the fishes themselves, settling into positions that typically defy the "Golden Ratio" and other human-created constructs.

As a reefer for decades, I learned a lot about balance, understanding that there is a certain amount of natural growth, such as coralline algae and such, which goes with the territory, and that a well-functioning and stable reef aquarium has achieved a certain balance between what we perceive as "nuisance" and "necessary." No reefer likes huge algae outbreaks, but every reefer appreciates the presence of some algae in his or her system, as well as the random appearance of various micro and macro-fauna.

A sort of acceptance of a "holistic" environment within the confines of our aquarium. It's one of the "foundation principles" of reef keeping, and I think it would serve many within the freshwater aquascaping community to study and appreciate this as well. Rather than simply appropriating the term "Nature" or "Natural" to describe our system, we should think about how Nature actually operates- and looks, and appreciate, emulate, and embrace the unusual look of botanical-style aquariums.

The "mental shift."

Far more than a barrier, really.

Rather, it's like a "point of demarkation" between what we have come to expect from an aquarium and indeed, Nature- and the way Nature wants to "evolve" our aquariums. There is a certain dynamic- perhaps even a "tension"- between expectation and reality, and the understanding of this, wether we embrace it or not- will only make us better aquarists, with a more complete appreciation of the natural world and how function and form unexpectedly combine to create beauty- if we make the effort to see it.

And when we see it, we're far more likely to want to preserve and protect it, and educate others about its wonders. Or replicate it in our aquariums!

To truly enjoy the botanical-style aquarium, you need to understand what's involved, what's required of you as a hobbyist, and then move forward. Just remember one thing when playing with "botanicals in the aquarium:

It's not a "plug-and-play" proposition. It requires some effort, thought, observation, and patience...

By observing and assessing on a continuous basis, you'll get a real feel for how botanicals work in your aquarium.  And what's the real "finesse" part of the equation? It's the nuance. The subtle, yet noticeable adjustments and corrections we make to keep things moving along nominally- sort of like pruning in a planted tank, or weeding a garden...it's a process.

Yeah, a process.

In fact, the entire experience of a blackwater, botanical-style aquarium boils down to a process and a pace that helps foster the gradual, yet inexorable "evolution" of the aquarium. And let there be no doubt- a botanical-style aquarium does "evolve" over time, regularly and steadily changing and progressing. As we've mentioned many, many  times before, it might be the perfect expression of the Japanese concept of "wabi-sabi", popularized by Takashi Amano, which is the acceptance of transience and imperfection.

A mindset. A point of view. A philosophy, for sure.

And the patience to allow your system to evolve. 

It's absolutely the most essential skill to have if you're going to work with botanical-style aquariums. Period. There are no shortcuts, major "hacks", or ways to dramatically speed up what Nature does. Why would you want to, anyways? 

Adopt a "long game" mindset.

Know that good stuff often takes time to happen. I'm personally not afraid to wait for results. Well, not to "just sit around" in the literal sense, mind you. However, I'm not expecting instant results from stuff. Rather, I am okay with doing the necessary groundwork, nurturing the project along, and seeing the results happen over time.

A "long game." 

That's what we play here.

It goes hand-in-hand with interpreting and recreating the form and function of Nature as it really is.

Uncomfortable with this idea?

I understand.

It's hardly "revolutionary" or crazy... Patience is something most hobbyist already have- or should have- in their metaphorical "toolkit." Trying to re-create Nature in the aquarium is as old as the hobby itself.


Yet, to attempt to really replicate one of these complex natural habitats in the aquarium in form and function requires us to look ourselves in the mirror and see if we're up to the challenges (aesthetic and otherwise).

Can you handle the detritus? The biofilm? The fungal growth? The decomposition?

Had enough of this stuff? Or are you thirsty for more?

I submit to you the next step- the idea of turbid, sediment-filled tanks, where dead branchy materials, decomposing leaves, twigs, biofilms, clays, soil and silt play...

It's our next example of replicating Nature in all of its unabashed glory.

This type of feature really pushes us out of our "comfort zone."

You have a substrate comprised of silty, sedimented material which, when disturbed, will cloud the water a bit for days at a time. Sort of like what happens in Nature- but it's in your living room.

Is that something you'd want?

Trying to circumvent or "edit" this look is easy- yet it simply glosses over the real beauty of Nature. The "rules" of Aquascaping which we embrace so willingly simply fly in the face of how Nature works.

Suffice it to say, there are NO rules about rediscovering the unfiltered art beneath the surface. Our "movement" believes in representing Nature as it exists in both form and function, without "editing" the very attributes of randomness and resulting function that make it so amazing.

We are utterly inspired by this.

And challenged by it.

We are all about the preservation of biofilms, decomposition, and that "patina" of biocover that exists when terrestrial materials contact water. We've come to the understanding that these materials break down and influence the environment...and that this process doesn't always conform to our hobby interpretation of what is "beautiful."

We've developed a keen appreciation for the ephemeral, the transitional. 

It makes sense to me. It makes sense to many of you, too.

I believe that there is a huge hunger in the aquarium hobby to find out more about the natural habitats from which our fishes hail, and to create more realistic functional representations of them in our aquariums.

In my own rebellious way, I also can't help but think that part of this enthusiasm which a growing number of aquarists seem to have for this stuff is that aquarium hobbyists in general have a bit of a "rebellious streak", too! Our taste in "style" is changing.

And that maybe, just maybe- we're collectively a bit- well, "over" the idea of the "rule-centric", mono-stylistic, overly dogmatic thinking that has dominated the aquascaping world for the better part of two decades.

We're ready to look at Nature- and our aquariums, in a different way.

We're ready to learn more- from the worlds we create. Because they follow the path which NATURE created.

Stay attuned. Stay observant. Stay open-minded. Stay humble. Stay brave...

And Stay Wet.


Scott Fellman

Tannin Aquatics 



July 06, 2020


A gift from The Master..

There is something neat about "ritual" in aquarium keeping. By ritual, I'm not talking about some religious service- I mean, ritual, in the sense that we engage in certain practices over and over on a repetitive basis.

In the botanical-style aquarium, we certainly do engage in many ritualistic behaviors, including replenishing our botanical "bed" in our aquairums as the materials break down and decompose.  

The continuous replacement and supplementation of leaves and botanicals as they start to break down is a sort of process- okay, maybe even a habit- which many of us who play with botanical-style aquariums engage in on a regular basis.  

And there are reasons for it: This practice not only creates a continuously evolving aesthetic, it helps maintain the biological diversity and helps ensure that environmental parameters within the aquarium 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.

Like, big, wholesale exchanges of old and new materials.

This is similar to the Japanese aquascaping practice of "sozo haishoku" espoused by the "Master" of this in aquariums, the late Takashi Amano. This 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.

Embracing and understanding this philosophy is a true gift from Nature. It offers the aquarist a chance to both experience natural processes, as well as to impact the evolution of his/her own closed microcosm in profound ways. 

Now, one thing that's unique about the botanical-style approach is that we tend to accept the idea of decomposing materials accumulating in our systems. We understand that they act, to a certain extent, as "fuel" for the micro and macrofauna which reside in the aquarium. The idea of leaving this material in place over the long-term is a crucial component of this approach, IMHO.

As we've discussed repeatedly, just like in Nature, these materials also form the basis of a  complex "food chain", which includes bacterial biofilms, fungi, and minute crustaceans. Each one of these life forms supporting, to some extent, those above...including our fishes.

I have long believed that if you decide to let the botanicals remain in your aquarium to break down and decompose completely, you shouldn't change course by suddenly removing the material all at once...Particularly if you're going to a new version of an existing aquarium.


Well, I think my theory is steeped in the mindset that you've created a little ecosystem, and if you start removing a significant source of someone's food (or for that matter, their home!), there is bound to be a net loss of biota...and this could lead to a disruption of the very biological processes that we aim to foster.

Okay, it's a theory...But I think I might be on to something, maybe? So, like here is my theory in more detail:

Simply look at the botanical-style aquarium (like any aquarium, of course) as a little "microcosm", with processes and life forms dependent upon each other for food, shelter, and other aspects of their existence. And, I really believe that the environment of this type of aquarium, because it relies on botanical materials (leaves, seed pods, etc.), is more signficantly influenced by the amount and composition of said material to "operate" successfully over time.

Just like in natural aquatic ecosystems...

Yeah, there is a natural "prototype" for this process:

As we talked about many times before, removing old materials and replacing them with new stuff 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. In Nature, the underwater "topography" is significantly affected by these events, removing old feats and replacing them with new ones.

On the "downside", it can also create significantly different environmental parameters when we do big "change-ups" of materials in a short span of time; the impacts on our fishes may be positive or negative, depending upon the conditions which existed prior to the move. 

Now, personally- I'm a fan of less "radical" moves, and in the interest of a good "offense", I favor regular, more measured 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.

The "Urban Igapo" idea that I've been touting for a good part of the year is a very deliberate execution of this iterative process, and it's taught me quite a bit about how these habitats function in Nature, and what kinds of benefits they bring to the aquarium. It's also taught me about the relentlessness of change and how habitats evolve over time.

We've talked about the idea of "flooding" an aquarium setup designed to replicate an Amazonian forest before. You know, sort of attempting to simulate some of the processes which happen seasonally in Nature. With the technology, materials, and information available to us today, the capability of creating a true "year-round" habitat simulation in the confines of an aquarium/vivarium setup has never been more attainable!

We've been testing the idea for a long time, and have been formulating some soils which attempt to replicate some of the attributes of those found in these habitats during the "dry" season. When flooded, you get an effect that's similar to what happens in the igapo. The debut of these "sedimented substrates", called "Nature Base", is just weeks away now. We think that they'll have a big impact on some of you.

And they will carry with them their own set of expectations: Sure, the water gets cloudy for a bit. The water is tinted, turbid, and sediment-laden. Eventually, it settles out. If you planted grasses and plants which are able to tolerate submersion for some period off their life cycle, they'll "hang on" for a while- until the waters recede.

Just like in Nature.

And you can go through multiple "wet and dry seasonal cycles" with the same substrate and perhaps only a slight addition of materials to replenish those which have broken down, but the result is a sort of "continuous aquarium"- one which can stay more-or-less intact over a long period of time and iterations, despite it's changes in appearance.

Some months back, did a slight "makeover" to my brackish water mangrove tank in my home office, which has accumulated a significant amount of decomposing mangrove leaf litter over the year it has been in operation. I wanted to add a lighter-colored, fine sandy substrate to be more consistent with some of the brackish-water Mangrove habitats I've studied. So what did I do? Well, I literally placed the sand on top of the accumulated leaf litter detritus... A pretty radical move for me!

And really, what happens is that, through the power of the current and the activities of my fishes, some of it rises up to the surface once again! And the water parameters have been unaffected by this move. With the understanding that we are attempting to foster multiple "levels" of life forms in our tanks, NOT removing all of the decomposing materials is a good move, IMHO.

Think about food chains, microbial growth, and environmental stability in our aquariums. Fostering these requires us to embrace, rather than fear- some of these processes as they happen in our tanks. 

And of course, Nature provides examples of similar processes!

Of course, I have no illusions that open, natural aquatic systems operate differently from our aquariums, but the "concept" is essentially the same... Study this pic by our friend, Tai Strietman taken in the Amazon...Leaves being covered by sand...interesting!

Nature really provides a "prototype" for everything, huh?

Having studied many images of Amazonian igapo, it is very obvious that, although some materials are swept away by currents, etc., many do 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, when coupled with good husbandry technique (ie; water exchanges, population management, feeding, and use/replacement of chemical filtration media) an eye for aesthetics, patience, and a focus on creating as complete-functioning a microcosm as possible in our tanks, long-term success is virtually a "given" in botanical-style aquariums.

Okay, emphasis on "virtually." Nothing is a complete "given" in this hobby!

Now, far be it from me to say that one of these systems won't test your patience, diligence, and perseverance- but to those who do endure and hold steady, the rewards are there. Facing, accepting, and dealing with some of the early "aesthetic challenges" in botanical-style aquariums, like the appearance and proliferation of biofilms, fungal growth, and the breakdown of botanicals is a fundamental step in building our "skill set" in this speciality.

It's simply a fact that terrestrial materials, which exposed to water, will decompose, recruit fungal and biofilm growths, and substantially impact the aquatic environment and the physical appearance of our tanks. Exactly like in Nature! And how we manage this stuff, both mentally and practically, will impact the state of the art in truly "natural" aquariums for years to come.

We need to evolve just like our tanks do.

For decades, the hobby focus has been all about removing pretty much everything as soon as it breaks down. Clinical "cleanliness" of sorts. I beg us to reconsider this long-held belief, and to think about the potential benefits of leaving botanical materials in until they completely break down.

So, if you're tempted to remove some decomposing leaves or broken-down botanicals to preserve some aesthetic you have in your head...think twice, okay? Preserve at least some of the old materials. Think about the long-term impacts of such short term moves. Do think about the ability of the life-forms in our tank to process and utilize these materials if left undisturbed.

Yes, consider the concept of "Sozo Haishoku", the transient nature of botanicals, and the evolution of your aquarium over time.

You might change the course of your aquarium- and you will almost certainly change the course of the hobby as a whole.

Embrace the gift from the Master- "sozo haishoku"- on a scale that makes sense for you and your aquariums inhabitants. 

Stay patient. Stay curious. Stay thoughtful. Stay consistent. Stay observant...

And Stay Wet.


Scott Fellman

Tannin Aquatics 



July 03, 2020


Plying the niches...

One of the coolest things about running Tannin Aquatics is that we are what is known in the business world as a "niche" business. That is, we serve a specialized area of the aquarium hobby- people who are interested in creating more natural-looking- and functioning- aquatic displays.

As such, we not only offer products catering to a specific area of interest in the aquarium hobby- we provide information and inspiration to help cultivate new ideas and advancements that keep things fresh and progressive. And with this obsession about serving a specialized area of interest, we have a keen understanding of what our community is interested in.

I am quite proud of the fact that we did our small part to help bring blackwater, botanical-style aquariums out of the metaphorical "shadows" and helped curate and disseminate new and hopefully more nuanced information and "best practices" stuff about working with these specialized systems- helping, along the way to dispel some long-held misconceptions and misinformation which likely kept more hobbyists from playing with them.

It's like that with a lot of speciality areas within the hobby. You could literally pick one- or a dozen- little aquarium hobby niches and find a whole lot of great people doing cool stuff and sharing their experiences- and an equal quantity of misinformation, second-hand "tips", and outright bullshit!

The other day, I was having an email exchange with a member of our community who was lamenting that the brackish water area of the hobby is still sort of in that "emerging" phase- essentially a "victim" of decades of scant hobby information, focus on the most superficial aspects, and second-hand reports. It was- and is- common to see discussion about brackish aquariums on forums prefaced with stuff like, "I've heard______."

That phrase typically turns me off. 

In fact, it often makes me want to vomit.

It's part of the modern narrative of the "keyboard benefactor" in the hobby- often a (well-intended) sharing of information by a hobbyist who has little or no personal experience or direct information about the subject being discussed...And what it leads to is further dissemination of often shaky, many times incomplete, and often simply wrong information. In short, these kinds of well-intended attempts at helping often have the exact opposite effect. They often contain information which discourages interested hobbyists from moving forward into the niche they're into.

And that's a tragedy, IMHO.

One of the questions which I am often asked by the uninitiated to our niche is, "Why do you add this stuff to your aquariums?" A truly foundational question, of course- yet one which literally makes us think through the entire process.

Obviously, we could go into the answer in great detail, but I think that we've more or less covered the "why?"part of the equation since day one in this column, so I won't go on and on about that! Suffice it to say, we play with botanicals in our aquariums because they help us to replicate- in some manner, the processes and conditions which occur in natural aquatic systems. 

It's as simple- and complex- as that.

It's all about replicating the look and function of Nature, and most important- helping to understand why.

And the most important thing is not to get too far out in front of this stuff and make wild assumptions. Although we can replicate some aspects of Nature, we don't have the technical means, at least at a hobby level, to verify all of the impacts of utilizing botanical materials in our aquariums. And we simply don't have a complete understanding of every function of a natural aquatic ecosystem and all of their functions and interactions..

And we simply don't know everything about botanicals and their use in our aquariums. 

And, that's okay.

To that end, you'll notice that, in this column and elsewhere, you won't see us making wild, broad assertions about what botanicals can and cannot do in aquariums.

Rather, we can report upon the impacts that we can see and quantify in our own aquariums, and research the potential impacts that these materials have. We can also study the botanical materials which accumulate in natural aquatic habitats, and attempt to understand their influences upon them. We can ask questions, entertain hypothesis, and experiment.

However, we don't make assertions about them, and we discourage our community not to, either. We can't- we shouldn't. 

I hate exaggerations, the perpetuation of myths, and the attribution of all kinds of capabilities to techniques, products, etc. in the hobby which are only marginally based in fact. Especially when these ideas are pushed out by people who may not have all of the facts, the personal experience, and/or the background to back them up. 

These things-no matter how well intentioned- become very detrimental to the hobby.

Now look, I realize that many times, these things are offered up with very good intentions; not with some "nefarious purpose" in mind. I mean, sure, sometimes you'll see someone who has a vested interest in selling something proffer these kinds of things, which flat-out sucks. I think it's far more beneficial in the long run, to simply acknowledge that they don't have 100% certainty about the benefits of their product, but that there are interesting results and potential benefits, and to encourage responsible experimentation.

That's what we do, and I think that it's just fine- if you communicate this effectively and openly.

In our niche, it's led to a tremendous amount of participation and good information being created for the hobby. We as a brand, and us as a community share our success, challenges, and outright failures openly. We all learn together. We don't simply "parrot each other"-regurgitating secondhand information- and that's great!

Unfortunately, in the aquarium hobby, it's not uncommon to see straight-up "regurgitations" by otherwise well-intended hobbyists, making strong assertions or statements about this stuff- good or bad- who simply didn't bother to do their "due diligence" and research the facts for themselves before pushing it out on the web with personal commentary.

Often, these people have no firsthand knowledge or experience with the stuff they are pushing out! You know, the aquarium equivalent of "re-tweeting" something just because.

Well, that sucks, too. Right?

It sucks because it doesn't really add to the body of knowledge we are trying so hard to accumulate. It sucks because it can perpetuate second-hand knowledge that may or may not be accurate.

It hurt our niche for years...In fact, it simply discouraged it from really evolving for many decades. No one really jumped in with gusto and the desire to progress, evolve, and expand upon the limited information that was out. As a result, the limited, often shaky- information out there already flourished and became the "standard bearer" of the niche.

That kind of stuff is actually kind of tragic in a lot of ways.

Simply perpetuating this stuff can really inhibit those who want to push forward carefully from even doing so-or just being a fraud to share their efforts. People are often afraid of  getting their ideas and experiences out there! Being "first" to do something in the aquarium hobby can be a real scary thing sometimes. Lots of people are "skeptics" or "armchair critics", who simply live to trash others who are trying something different. I see it a lot. And I think it's okay to be the first to do something previously seen as "crazy" or "risky" or "unorthodox" in the hobby.

Someone who has to be the first to accomplish something great.

Someone who can overlook the negativity and "smack talk", to fly in the face of convention while taking that road less traveled. This is how we progress. This is how we will continue to progress in the hobby. And more important, this is how we inspire a new generation of hobbyists to follow our lead, for the benefit of both the hobby and the animals that we enjoy.

We can't dispense advise to fellow hobbyists with a dogmatic attitude that discourages progress and responsible experimentation. It will simply stagnate the progress of the hobby we all love.

And of course- my "call to arms" to ply new niches in the hobby comes with a request that you temper this with common sense.

I’m not advocating the abandonment of common sense and healthy skepticism. Everyone should not make a mad dash to the LFS to assemble schools of Black Diamond Stingrays. What I AM pushing is that we (and by “we” I mean every one of us in the hobby) should encourage fellow hobbyists who want to experiment and question conventional wisdom to follow their dreams.

If someone has an idea- a theory, and some good basic hobby experience, there is certainly nothing wrong with that. Yes, there is the sad fact that some animals might be lost in the process. It sucks. It’s hard to reconcile that…and harder to stand by it when animals are dying.

However, that may be the cost of progress.

The cost of not progressing might be far higher:

The loss of countless species in the wild whose habitats are being destroyed, while those of us with some skills, dreams and respect for the animals sit by idly -watching them perish, failing to even attempt captive husbandry and propagation for fear of criticism and failure from the masses. There has been very real talk over the years about making the importation, and possibly the distribution- of live corals and some fishes illegal in many nations. It's not that unrealistic a possibility. Who knows what opportunities might be missed if we fail to persue our goals?


Let's keep working together to push the state of the hobby farther than ever, backed up with facts and personal experiences! Of course, you should share your theories and hypothesis- but you should identify them as such. And guess what? When we aren't sure about something, there is absolutely no shame in saying, "We're just not sure..."

Everybody wins that way. Especially the animals we love so much, and the habitats we're fascinated by.


And there is something really interesting about our hobby "work"-especially in our little niche.


There's been a fair amount of research and speculation by both scientists and hobbyists about the processes which occur when terrestrial materials like leaves and botanical items enter aquatic environments, and most of it is based upon field observations by scientists and ecologists.

As hobbyists, we have a unique opportunity to observe firsthand the impact and affects of this material in our own aquariums! I love this aspect of our "practice", as it creates really interesting possibilities to embrace and create more naturally-functioning systems, while possibly even "validating" the field work done by scientists! 

It goes without saying that there are implications for both the biology and chemistry of the aquatic habitats when leaves and other botanical materials enter them.

THAT is the real value of experimenting- pushing outwards...plying the niches and backwaters of the aquarium hobby.

Cast off..

Stay brave. Stay curious. Stay unabashed. Stay confident. Stay open-minded...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


July 02, 2020


Shallow thoughts...

I suppose tastes change in the hobby over time...I certainly know that MINE do!

For example, my feelings about small tanks have come full-circle over the years. I've really come to enjoy them- for a lot of reasons, really...not the least of which is that they can serve as a sort of reliable and easy-to-iterate "test bed" for lots of new ideas.  

In particular, lately I'm really fond of shallow, rather wide aquariums. The unique dimensions of such tanks gives you interesting possibilities to create simple, yet utterly fascinating displays.

And of course, this makes some sense when you contemplate the types of aquatic habitats I'm drawn to. Like, here at Tannin, we're crazy about small, shallow bodies of water, right?

Especially little rivulets, vernal pools, creeks, and forest streams.

The kinds which have an accumulation of leaves and botanical materials on the bottom. The environments which are often shaded, loaded with twigs, and replete with tinted water... 

You know, the kind where you'll find fishes!

Happily, such interesting aquatic habitats exist all over the world, leaving us no shortage of inspiring places to attempt to replicate.

In Africa. many of these little streams are home to some of my fave fishes, killifish!

As mentioned above, these little jungle streams are really shallow, cutting gently through accumulations of leaves and forest debris.  Many are seasonal. The great killie documenter/collector, Col. Jorgen Scheel, precisely described the water conditions found in their habitat  as, "...rather hot, shallow, usually stagnant & probably soft & acid."

Ah-ah! We know this territory pretty well, right?

I think we do...minus the "stagnant" part, of course...

And understanding this type of habitat has lots of implications for creating very cool biotope-inspired aquariums. 

And why not make 'em for killifish?

So, for the most part, these fishes are often found in very shallow jungle streams. How shallow? Well, reports I've seen have stated that they're as shallow as 2 inches (5.08cm). That's really shallow. Seriously shallow! And, quite frankly, I'd call that more of a "rivulet" than a stream! "Virtually still, with a barely perceptible current..." was one description.

That kind of makes my case.

What does that mean for those of us who keep small aquariums?

Well, it gives us some inspiration, huh? Ideas for tanks that attempt to replicate and study these compelling shallow water environments...

Now, I don't expect you to set up a tank with a water level that's 2 inches deep..Well, it would be pretty cool...Yet, that's kind of extreme. For more of us, perhaps a 3.5"-4" (8.89-10.16cm) deep depth is something that can work? Totally doable. There are some pretty small commercial aquariums that aren't much deeper than 8" (20.32cm), and you could adapt other containers for this purpose, right? 

We could do this with some of the very interesting South American or Asian habitats, too...Shallow tanks, deep leaf litter, and even some botanicals for good measure.

Fishes like "Darter characins" and the like can do very well in such conditions. In fact, many small tetras can. If you remember, we ran a very successful "all leaf litter" tank with the "Green Neon Tetra" a while back, and it was one of the most interesting systems I've ever played with.

I only filled this tank to a depth of around 5 inches ( 12.7cm) at the most. But I used  a lot of leaves to cover the bottom. I used "Texas Live Oak Leaf Litter", "Nano" Catappa leaves, and Yellow Mangrove leaves. The result was a deeply tinted aquarium with very little in the way of vertical relief.  At first, you'd think this would be just incredibly boring.

It wasn't.

The fishes were not only stunning to look at against this interesting "substrate", they displayed a remarkable set of behaviors, such as a "cooperative foraging" among the leaves, with every individual in the shoal taking part- that I had not seen before. Some would dive in and pick at "something", while the remainder would sort of "hold station" above the leaves. This behavior would go on for hours! It was neat to watch. 

I've often fantasized about a long, low, shallow aquarium with just a fine sand substrate and a few pieces of driftwood- perhaps an interesting habitat for Corydoras or other small catfishes. I've seen images of habitats like this from our friend, David Sobry, taken in The Amazon- and they're quite compelling!

Even the idea of a near "wood-free" shallow stream, with riparian vegetation on the "banks" would be fascinating to recreate in the aquarium. Utilizing a correctly-sized aquarium would deliver a unique look, above and below the water surface. 

And of course, the tropical habitats of the world don't limit you to sand and branches and leaves for your "hardscape..." You can also create very interesting rock-based systems, right?

Again some "Darter characins" (Characidium sp.) would work in such an aquarium, as would Hillstream loaches and other interesting fishes in habitiats designed to replicate Asian biotopes. There is a lot of interesting stuff to take away from these habitats.


Streams are really amazing habitats for us to play with. There is so much interesting stuff to take away from them. And a whole science to their structure and function that is filled with takeaways for the aquarist.

The definition of a "stream" is: "...a body of water flowing in a channel or watercourse, as a river, rivulet, or brook..."

And of course, these little bodies of water flow through jungled areas, where they're bound to pick up some leaves, twigs, and other plant parts as they wind along their path. Leaves, the "jumping off point" of our botanical obsession, form a very important part of these stream habitats.

It is known by science that the leaf litter and the community of aquatic animals that it hosts is, according to one study, "... of great importance in assimilating energy from forest primary production into the blackwater aquatic system." 

It also functions as a means to preserve the nutrients that would be lost to the forests which would inevitably occur if all the material which fell into the streams was simply washed downstream. The fishes, crustaceans, and insects that live in the leaf litter and feed on the fungi, detritus, and decomposing leaves themselves are very important to the overall habitat.

In the aquarium, leaf litter and botanicals certainly perform a similar role in helping to sequester these materials.

Some litter beds form in what stream ecologists call "meanders", which are stream structures that form when moving water in a stream erodes the outer banks and widens its "valley", and the inner part of the river has less energy and deposits silt- or in our instance, leaves.

There is a whole, fascinating science to river and stream structure, and with so many implications for understanding how these structures and mechanisms affect fish population, occurrence, behavior, and ecology, it's well worth studying for aquarium interpretation!  Did you get that part where I mentioned that the lower-energy parts of the water courses tend to accumulate leaves and sediments and stuff?

It's logical, right?

And it's also interesting, because, as we know, fishes and their food items tend to aggregate in these areas, and embracing the "theme" of a litter/botanical bed or even wood placement, in the context of a stream structure in the aquarium is kind of cool!

The big takeaway here?

Research jungle stream or pool ecology. Study images and videos of these natural habitats. Learn which fishes are found in them. Try replicating those super-shallow aquatic environments with nano tanks. Keep the water in the tank shallow. Add leaves and stuff.

Observe. Explore. Enjoy. 


Stay inspired. Stay fascinated. Stay creative. Stay engaged...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

June 29, 2020


Just, like...maintain...okay?

We receive a lot of questions about the maintenance of botanical-style aquariums. And it makes a lot of sense, because the very nature of these aquariums is that they are stocked, chock-full of seed pods and leaves, all of which contribute to the bio load of the aquarium- all of which hare in the process of breaking down and decomposing to some degree at any given moment.

It's not so much if you have to pay attention to maintenance with these tanks- it's more of a function of how you maintain them, and how often. Well, here's the "big reveal" on this: 

Keep the environment stable.

Environmental stability is one of the most important- if not THE most important- things we can provide for our fishes! To me, it's more about doing something consistently than it is about some unusual practice done once in a while.

Like, ya' know- water exchanges.

Obviously, water exchanges are an important part of any aquarium husbandry regimen, and I favor a 10% weekly change. Iit's the regimen I've stuck with for decades, and it's never done me wrong. I think that with a botanical influenced aquarium, you've got a lot of biological material in there in addition to the fishes (you know, like decomposing leaves and softening seed puds- stuff like that), and even in well-managed, biologically-balanced aquarium, you still want to minimize the effects of any organics accumulating in a detrimental manner. 

This piece is not really about water changes, and frankly, you can utilize whatever schedule/precentage works for you. The 10%-20% weekly has worked for me; you may have some other schedule/percentage. My advice: Do what works for you and adjust as needed.

Just do something.

Another question that we hear all the time around here is wether we should let the leaves in our tanks remain as they decompose completely, or remove them after they begin to break down.

Depending upon my "mood de jour", I may elect to keep leaves and botanicals in my system until they completely decompose. Ing an otherwise well-managed aquarium, this is generally not a water-quality-affecting issue, in my experience, and is more a matter of aesthetic preferences. There are times when I enjoy seeing the leaves decompose down to nothing, and there are other times when I like a "fresher" look and replace them with new ones relatively soon.

Some individual leaves and botanicals "recruit "an inordinate amount of biofilms, which even I may find distracting (hard to believe, I know...), so I will typically remove those "offenders". Again, no harm in leaving them in; the presence of biofilms indicates the presence of beneficial bacteria just doing their thing. It's just that sometimes, you don't want them doing too much of their thing- or in a place where you have to look right at it every day! You can remove sections of it with a planting tweezer (tedious, but oddly relaxing and satisfying, I might add), or a siphon. Of course, as mentioned above, you can just yank the offending botanical right out of the tank and be done with it, too!

When leaves and botanicals break down completely, you end up with a fair amount of "stringy fungal growth, biofilms, and fine particles of decomposed leaves that tend to accumulate here and there in healthy aquariums.

What's cool about this stuff is that, not only do you see it in aquariums- you see it extensively in natural ecosystems, such as Amazonian streams, Asian peat swamps, and other habitats.

Of course, in the case of a "botanical" style aquarium, It's an integral component of  what we call an "enriched" substrate. As botanicals break down- just like in Nature- they create a diverse matrix of partially decomposing plant materials, pieces of bark, bits of algae, and some strings of biofilm.

Ahh, "detritus..."

Stuff that sounds diverse, and it's also benign. Of course, in the aquarium hobby, it's all classified as "detritus." Detritus seems to have a bit more of a sinister connotation to it. 

The definition is a bit more precise:

"Detritus is dead particulate organic matter. It typically includes the bodies or fragments of dead organisms, as well as fecal material. Detritus is typically colonized by communities of microorganisms which act to decompose or remineralize the material." (Source: The Aquarium Wiki)

Well, shit- that sounds bad! 

It's one of our most commonly used aquarium terms...and one which, well, quite frankly, sends shivers down the spine of many aquarium hobbyists. And judging from that definition, it sounds like something you absolutely want to avoid having in your system at all costs. I mean, "dead organisms" and "fecal material" is not everyone's idea of a good time, ya know?

Literally, shit in your tank, accumulating. Like, why would anyone want this to linger- or worse- accumulate- in your aquarium?

Yet, when you really think about it and brush off the initial "shock value", the fact is that detritus is an important part of the aquatic ecosystem, providing "fuel" for microorganisms and fungi at the base of the food chain in aquatic environments. In fact, in natural blackwater systems, the food inputs into the water are channeled by decomposers, like fungi, which act upon leaves and other organic materials in the water to break them down. 

And the leaf litter "community" of fishes, insects, fungi, and microorganisms is really important to these systems, as it assimilates terrestrial material into the blackwater aquatic system, and acts to reduce the loss of nutrients to the forest which would inevitably occur if all the material which fell into the streams was washed downstream!

That sounds all well and good and well, grandiose, but what are the implications of these processes- and the resultant detritus- for the closed aquarium system?

In years past, aquarists who favored "sterile-looking" aquaria would have been horrified to see this stuff accumulating on the bottom, or among the hardscape. Upon discovering it in our tanks, it would have taken nanoseconds to lunge for the siphon hose to get this stuff out ASAP!

In our world, the reality is that we embrace this stuff for what it is: A rich, diverse, and beneficial part of our microcosm. It provides foraging, "Aquatic plant "mulch", supplemental food production, a place for fry to shelter, and is a vital, fascinating part of the natural environment. 

It is certainly a new way of thinking when we espouse not only accepting the presence of this stuff in our aquaria, but actually encouraging it and rejoicing in its presence! 


Well, not because we are thinking, "Hey, this is an excuse for maintaining a dirty-looking aquarium!"


We rejoice because our little closed microcosms are mimicking exactly what happens in the natural environments that we strive so hard to replicate. Granted, in a closed system, you must pay greater attention to water quality, but accepting decomposing leaves and botanicals as a dynamic part of a living closed system is embracing the very processes that we have tried to nurture for many years.

And it all starts with the 'fuel" for this process- leaves and botanicals. As they break down, they help enrich the aquatic habitat in which they reside. Now, in my opinion, it's important to add new leaves as the old ones decompose, especially if you like a certain "tint" to your water and want to keep it consistent.

Not only does adding new leaves keep the water tint (and parameters, once you dial 'em in) consistent, it also gives you a sort of "evolving" aesthetic, which is similar to what you'll see in Nature: newly fallen leaves replacing older ones that have decomposed. Botanical system can be very dynamic in this way!

And then, there's that whole "water color" thing...

Like many of you, I store my water in plastic containers for use during water changes. Over the years, I've sort of worked out a rough "formula", if you will, to create consistent "tint" and conditions for my makeup water. Typically, I'll add 3 medium-sized Catappa leaves to a 5 U.S. gallon container of RO/DI water. This has always given me a nice even color and a pH around 6.5-6.6, which is the range I maintain in my display aquariums.

Hardly an exact science, I know.

Now, "your mileage may vary" as they say, and perhaps a different number of leaves in a different sized container works for you. Obviously there are many variables, even in as simple a practice as steeping leaves in your makeup water, like the source of the leaves and their "potency" (in regard to tannins contained in their tissues), the age and condition of the leaves, temperature, etc., etc., etc.

Oh, and then there's that recommendation to test your water. Yeah, that's me. And you don't need to go crazy, but regular tests of pH, alkalinity are really important when you're flirting with soft, acid water systems. And checking phosphate and nitrate are never a bad thing, as they can give you an insight into trends within your system, as well as just good old-fashioned knowledge about how your system tends to operate once it settles in.

Although it IS possible to have too much information (to the point where you can obsess over what are really insignificant details), it's never a bad thing to have enough to spot trends, right?

People ask a lot if blackwater tanks are tricky to maintain, given the reputation for challenges in low pH, soft water systems and the more delicate fishes traditionally associated with them (like Discus and Wild Angelfish, etc.). Honestly, I don't think they are any more "difficult" to care for than any other type of aquarium.

Definitely easier than say, a Rift Lake cichlid tank- and a magnitude easier than a full-blown reef system (or coral propagation facility, as I can attest to!). Like anything else, you'll develop the techniques, skills, and systems to manage your system in a manner that works for you and your fishes- and that's really all you need to do, in my opinion!

Observation- just looking at your fishes and their aquariums- goes a long way towards success in ANY type of aquarium. With hobbyists busier than ever before, with more personal and other demands vying for attention, this obvious thing may not be as easy as it used to be- so make it a point to spend some time every day just looking at your aquarium.

The longest I've personally maintained such a system has been about 5.5 years, and the only reason I broke down that aquarium was because of a home remodel that required the removal of everything from the space in which the aquarium was located. I set it up again shortly after the work was completed. The reality, though, is that I could have kept this system going indefinitely. 

As most of you who work with these aquariums know, the key to long-term success with them is to go slowly, deploying massive amounts of patience, common-sense husbandry, monitoring of environmental parameters, and careful stocking management. Not really much different from what you'd need to do to successfully maintain ANY type of aquarium for the long haul.

Yeah, real "news flash" there, right?

So, it all starts with the way these tanks "run in", and that will sort of "set the tone" for the care and long-term maintenance involved. 

Expectations, if you will.

First off, one of the things that we all experience with these types of systems is an initial burst of  tannins, which likely will provide a significant amount of visible "tint" to the water. If you're not using activated carbon or some other filtration media, this tint will be more pronounced and likely last longer than if you're actively removing it with these materials! And, if you use too much carbon, you'll be one of those people who emails me with a starting line like, "...and I added an entire package of catappa leaves and my water is barely tinted..."

You might also experience a bit of initial cloudiness or turbidity...this could either be physical dust or other materials released from the tissues botanicals, or even a burst of bacteria/microorganisms. Not really sure, but it usually passes quickly with minimal, if any intervention on your part. Oh, and not everyone experiences this...often this is a phenomenon which seems to happen in brand new tanks...so it might not even be directly attributable to the presence of the botanicals (well, at least not 100%). Could be the sand, or other dust/dirt from the other hardscape materials or the tank itself.

Oh, and the reality is that in a tank with lots of botanical materials, the water may not always be "crystal clear." I mean, sure it'll be clear- as in, you can see across it- but it might have a sort of "soupy" look to it. This is for the very reasons stated above. Mental shifts required...

So, that being said...what happens next?

Well, typically, as most of you who've played with this stuff know, the botanicals will begin to soften and break down over a period of several weeks. Botanical materials are the very definition of the word "ephemeral." Nothing lasts forever, and botanicals are no exception! Pretty much everything we utilize- from Guava leaves to Melostoma roots- starts to soften and break down over time. Most of these materials should be viewed as "consumables"- meaning that you'll need to replace them over time.

I'll backtrack and touch on that whole idea of "leaving stuff in" to break down fully.

I have never had any negative side effects that we could attribute to leaving botanicals to completely break down in an otherwise healthy, well-managed aquarium.

Many, many hobbyists (present company included) see no detectable increases in nitrate or phosphate as a result of this practice. Of course, this has prompted me to postulate that perhaps they form a sort of natural "biological filtration media" and actually foster some dentritifcation, etc. I have no scientific evidence to back up this theory, of course (like most of my theories, lol), other than my results, but I think there might be a grain of truth here!

So, the living with your botanical-style backwater aquarium isn't just about a new aesthetic approach. This is where the "mainstream aquarium crowd" (LOL) gets it all wrong and really "short-sells" this stuff... It's about understanding and processing what's happening in the little aquatic ecosystem you've created. It's about asking questions, modifying technique, and, yeah, playing hunches- all skills that we as hobbyists have practiced for generations.

When you distill it all- we're still just "keeping an aquarium"-but one that I feel is a far more natural, dynamic, and potentially game-changing style for the hobby.

So, relax, observe, and...just maintain. Your aquarium will be fine.

Stay diligent. Stay consistent. Stay aware. Stay involved...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


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