February 14, 2019


Preservation of the patina..

The other day, I had someone ask me, "... if Tannin is going to offer ________ brand of products, and more of ____________ , to become a 'more mainstream shop' in the hobby" (his words), and it made me immediately shudder a bit, and reflect on the "state of play" in our little corner of the aquarium world; where we are, how we see it, and what we're doing here.

My point of view looks at things a bit differently. 

It ain't pretty. Some of you won't like my tone here. I'm warning you:

There is a point in the aquarium hobby where you start looking at your 11,000th Instagram feed post of a aquascape with " ____ Stone" and "Blah, blah, blah Grass" and the requisite branching wood soaring out past the waterline, anointed as a tank which "embraces Nature", and you kind of want to...well, vomit.

Well, I do.


I'm at that point.

"Oh, you're such a badass, Fellman. You and Tannin are cool and everyone else sucks..."


At least hear me out, where I'm coming from..Then you can trash me if you want.

How many tanks with crystal-white sand, crisp green manicured lawns of Eleocharis, 36 Cardinal Tetras, and grey rock do we have to see, with the accompanying adulations about how "amazingly natural" the tank looks before we take our heads out of (a certain part of our anatomy) and realize there is way more to creating a "natural aquarium" than the "paint-by-numbers" aesthetics-first social media fodder that's "top of feed" every day?

Yes, haters- come flame me... I Know I sound sorry of spiteful, or jealous or something...But that's not what I'm getting at. These tanks are great. For what they are. They are to the wild aquatic habitats what a flower arrangement is to a meadow.

They are beautiful. They are the result of very talented aquascapers doing great work. However, I think it's kind of absurd that we tout them as some ultimate expression of nature. No, they are an expression of part of nature.

And that's okay.

Yet, as the old show biz sayings goes, "Is that all there is?"

I mean, to me, they're just sort of all the same. They seem to be set up solely for the aesthetics and the function of them as an underwater microcosm of life, featuring relationships and biological interdependencies is essentially lacking. 

Or at least, discussion about anything other than how the f---ing plants are trimmed or what brand of soil additive or designer stone is used is curiously lacking.


Enough. Again, enjoy the hobby how you want to. It's okay. It's the way it should be. But the over-reaching narrative about this type of thing?

Tannin is not going to become a part of that. 

Our coined term, "functional aesthetics" sort of shows our positioning here. Emphasis on "functional." The "aesthetics" part comes from accepting the beauty of Nature as she is.

Our original mission at Tannin was to share our passion for the reality of "unedited" Nature, in all of its murky, brown, algae-patina-enhanced glory. And I started to realize that a while back, we were starting to fall dangerously into that noisy, (IMHO) absurd, mainstream aquascaping world. Pressing our dirty faces against the pristine glass, we were sort of outsiders looking in...the awkward, different new kid on the block, wanting to play with the others.

Then, the realization hit that we never really wanted to play like that. It's not who we are.

We are not going to play there.

We're going to double down in our dirty, tinted, turbid, decomposing, inspired-by Nature world. Sure, our materials can and should be utilized by all sorts of hobbyists for all sorts of applications. However, if you were worried about your favorite little quirky supplier of twigs and nuts becoming yet another "player" in the world of homogenized, prepackaged, generic blah, let me assure you now that it will not be happening.

We're all-in on the "preservation of the patina." Biofilms. Detritus. Decomposing leaves... Letting Nature do here thing and not "sanitizing it."

Yes, you'll see more and more unique stuff from us to help you embrace Nature as it is and incorporate it into your aquarium work. And we'll continue to feature blogs and information that highlights aspects of the natural aquatic habitats that we can and should incorporate into our aquarium work. Aspects that focus as much- if not more- on the function, as opposed to just the aesthetics- which will arise as a result of embracing natural processes.

Looking at stuff that's literally right in our faces, yet curiously not applied to aquarium work- is our "jam." Stuff like seasonal changes in aquatic habitats and figuring out how to apply them in our tanks is exciting and quite likely, ground-breaking concept in the hobby for those who choose to work with it.

Hmm. Seasonality. "What do you mean, Scott?"

Amazonian seasonality, for example, is marked by river-level fluctuation, also known as "seasonal pulses." The average annual river-level fluctuations in the Amazon Basin can range from approximately 12'-45' /4–15m!!!  Scientists know this, because river-water-level data has been collected in some parts of the Brazilian Amazon for more than a century! The larger Amazonian rivers fall into to what is known as a “flood pulse”, and are actually relatively predictable.

And of course, when the water levels rise, the fish populations are affected in many ways. Rivers overflow into surrounding forests and plains, turning the formerly terrestrial landscape into an aquatic habitat once again.

What can we learn from these seasonal inundations, besides just the obvious "structural" impact on the environment? You know, the water level rises... 

Well, for one thing, we can observe the impact of this cycle on the diets of our fishes.

Yeah, what they eat at different times of the year.

In general, fish, detritus and insects form the most important food resources supporting the fish communities in both wet and dry seasons, but the proportions of invertebrates fruits, and fish are reduced during the low water season. Interestingly, individual fish species exhibit diet changes between high water and low water seasons in these areas...a fascinating adaptation and possible application for hobbyists?

Even specialized feeders, like herbivorous fishes- make these changes. 

The consumption of fruits in Mylossoma and Colossoma species was significantly less during the low water periods, and their diet was changed, with these materials substituted by plant parts and invertebrates, which were more abundant. Fruit-eating is significantly reduced during the low water period when the fruit sources in the forests are not readily accessible to the fish.

During these periods of time, fruit eating fishes ("frugivores"-yeah, that's a thing) consume more seeds than fruits, and supplement their diets with foods like as leaves, detritus, and plankton. Interestingly, even the known "gazers", like Leporinus,  were found to consume a greater proportion of materials like seeds during the low water season.

And the inundation itself creates impacts which influence both the availability and production of foods. Mud and detritus are transported via the overflowing rivers into flooded areas, and create a layer of organic materials which contribute to the forest leaf litter and other botanicals, becoming nutrient sources which contribute to the growth of epiphytic algae and microorganisms.

During the lower water periods, this organic layer helps compensate for the shortage of other food sources. When the water is at a high period and the forests are inundated, many terrestrial insects on the surrounding trees fall into the water and are consumed by fishes. In general, insects- both terrestrial and aquatic, support a large community of fishes.

So, it goes without saying that the importance of insects and fruits- which are essentially derived from the flooded forests, are reduced during the dry season when fishes are confined to open water and feed on different materials. 

So I wonder...is part of the key to successfully conditioning and breeding some of the fishes found in these habitats altering their diets to mimic the seasonal importance/scarcity of various food items? In other words, feeding more insects at one time of the year, and perhaps allowing fishes to graze on detritus and biocover at other times?

Is the concept of creating a "food producing" aquarium, complete with detritus, natural mud, biofilms, and an abundance of decomposing botanical materials, a key to creating a more realistic feeding dynamic, as well as a "functionally aesthetic" aquarium?

Let's face it, a truly "natural" aquarium needs to embrace stuff like detritus, mud, wood, decomposing botanical materials, varying water tint and/or clarity, etc. The aesthetics might not be everyone's cup of tea, but the possibilities for creating more self-sustaining, ecologically sound microcosms are numerous, and the potential benefits for fishes are many. 

Just looking at Nature as it presents itself  and learning more about the dynamics of natural habitats and the ecology of the surrounding terrestrial environments is a  fascinating and compelling area of study that we as aquarists can really get into.

Yes, it requires some study of some esoteric things.

It requires trying some new and seemingly wacky ideas (encouraging the accumulation of detritus and epiphytic algal growth, for one thing), and embracing some different aesthetics. It requires us to get out of our own head space and separate superficial aesthetics from functional aesthetics. Can't wean yourself off of "aesthetics first?" Try this: Look at pictures of the natural aquatic habitats of the world instead of last month's "Tank of The Month", and ask yourself what occurs in Nature to make them appear the way they do.

Then, apply this to your next tank.

Free your mind.

Preserve the "patina" of life.

The potential for learning new things about our fishes, and perhaps being able to spawn them more reliably and productively, lessening our reliance on the collection of some wild specimens, and taking pressure off of the wild habitats, could be significant.

Stay observant. Stay curious. Stay diligent. Stay unique. Stay bold...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

February 12, 2019


Into the weeds.

I hate to be the one to break it to you:

We've got it all wrong.

We've been getting it all wrong.

Yeah, I know that hurts. It's crazy. But I think that it's true.  

A century or more of aquarium keeping, and I think the bulk of us in the hobby are still not quite "getting it." We "sanitize" Nature. We look for "shortcuts" to accomplish what Nature has been doing for eons. We attempt to circumvent the processes and what many of us consider the "ugly" parts of Nature.

We resist. We fight. We go halfway. And yet, we laud ourselves for creating "natural aquariums."

We're pretty close, in some respects. But we miss by a mile in others.

Now, sure, there ARE aquatic habitats in Nature which are more-or-less crystal clear, sparkling, and filled with plants and white sand- just like in our aquariums. However, the reality is that many- if not most-natural aquatic habitats are replete with leaves, twigs, plant parts, and, for want of a better word- "dirt."

Even the "crystal clear" ones aren't quite as pristine as we fantasize them to be. And of course, many are far more "dirty" than we realize. And our label of "dirty" doesn't equal "bad." 

And that's where we find the real magic, IMHO.

In this world of decomposing leaves, submerged logs, twigs, and seed pods, there is a surprising diversity of life forms which call this milieu home. And each one of these organisms has manages to eke out an existence and thrive.

It's Nature at her most beautiful.

And "natural."

Yet, we have been taught for generations to siphon out detritus, scrub algae, and remove decomposing plant materials. On the surface, these are the tenants of good husbandry for aquariums: Remove stuff that can degrade water quality before it has the opportunity to do that. 

I get it. 

However, think about it. These things occur in Nature for a reason. They play a vital role in the function- and yeah, the aesthetics- of natural aquatic habitats.

A lot of hobbyists not familiar with our aesthetic tastes will ask what the fascination is with throwing leaves, palm fronds and seed pods into our tanks, and I tell them that it's a direct inspiration from nature! Sure, the look is quite different than what has been proffered as "natural" in recent years- but I'll guarantee that, if you donned a snorkel and waded into one of these habitats, you'd understand exactly what we are trying to represent in our aquariums in seconds!

We also happen to like the way it looks, of course! 

And, to apply what we see in Nature to the aquarium requires a real "mental shift", as we've preferred here for some time now. With our "mental shift" that embraces the use of a melange of botanical materials, breaking down and recruiting some biofilms and such- just like in nature- I think we're on the verge of seeing more truly remarkable displays emerging, with greater functional and aesthetic authenticity than has previously been seen. 

I think that in our zealousness to make things easy and accessible for everyone, we've replaced studying how Nature does things with our penchant for learning how to use gadgets, additives, and other processes in an attempt accomplish the same thing. I can't help but think that these things create a different sort of "dependency", despite the hobby/industry's effort to make everyone "successful" in the hobby.

How do we reconcile this? How do we "re-establish" our connection with Nature?

The first step is to let go of some long-held preconceptions and to meet Nature where it IS, instead of where we WANT it to be. When we fight Nature by removing, say, all of the detritus in our tanks- we are quite literally "breaking the cycle" and depriving various groups of microfauna the environment and food source they need to carry out their life functions-which happen to include metabolizing organics and such...

And, think about it: Removing stuff near the bottom of the chain significantly affects stuff at the "top"- ie; our fishes, and the aquarium as a whole.

Again, I believe that we tend to become dependent solely on our filters, filter media, the large water exchange. Equipment and processes designed to circumvent the "pitfalls" of having decomposing organics and such in our tanks.

Now look, I'm not advocating ditching filters, skipping water exchanges (indeed, I am an advocate of more frequent ones), and just disregarding a century of aquatic "best practices" for husbandry.


However, what I am asking you to do is to reconsider why we utilize these things. What purpose do they serve? How do they sere this purpose? And to ask ourselves if we can use our knowledge and equipment to better work with Nature to accomplish the same things, rather than to fight off, circumvent, or eliminate some of these processes in our zeal to "sanitize" what Nature has successfully done for eons.

What if we encouraged decomposition; the microfauna who perform this role, and the growth of biofilms which metabolize organics and excess nutrients, rather than took the siphon hose to them at first opportunity? What if, rather than being alarmed by the appearance of this stuff in our tanks, we took it as a positive that Nature is working her magic, deploying the correct life forms to help utilize the abundance in our closed systems?

What if we encouraged these processes, rather than disrupted them because...well..because that's what we have been doing.

Guess what? An aquarium can still be beautiful while embracing all of Nature.

You can create aesthetics that can challenge just about any competition scape out there. The great Takashi Amano himself actually proffered this more than a decade ago...and somehow, this got utterly lost in the frenzy to replicate his work. He wasn't asking us to replicate his work. 

He was asking us to replicate the work of Nature.

This was a man who would literally lie down in a field of weeds and enjoy the subtle, yet intricate web of life that was present in the most esoteric of natural settings.

He got it.

It's time to get down into the weeds again.

Stay curious. Stay bold. Stay original. Stay observant...

And Stay Wet.


Scott Fellman

Tannin Aquatics 




February 10, 2019


My greatest mistake...Lessons for the "Kissing Gourami"

We all remember those first aquarium we were exposed to, right? You know, the ones that started this whole crazy hobby adventure for us?  Or perhaps, as in my case...the obsession was already in place, but something happened which made it worse! 

I remember an aquarium, way back when I was probably 8-9 years old, which captivated my attention. It was at my sister's friend's house- right smack in the entryway to their home:  What I believe to be a 40 gallon "Show" tank (based on my recollection of its size and proportions). It was on one of those ubiquitous metal type stands, straight out of the early 1970's, decorated with hanging fishing nets and dried starfish- you know, pure kitsch!

Yet, this particular aquarium captivated me like few other things did at the time. I used to love when my sister would drag me over to her friend's house, because I'd just park myself in front of the tank, and do what comes naturally for a fish geek- Just fully "geek out" in front of it, taking it all in...

In addition to the turquoise-colored gravel, petrified wood, and plastic plants, the tank had another appeal for me: A cool variety of fishes, including what I thought was the coolest thing out there at the time: a group of "Kissing Gourami", Helostoma temminckii. Of course, at the time, I was enamored by its goofy appearance, calm demeanor, and the iconic "kissing" behavior that would occasionally occur. 

(Pic by Green Yoshi used under CC BY-S.A. 3.0)

Now, at the time, I had no idea that this was a behavior that took place between rival males (and females, too, so I've heard) and was sort of the equivalent of a "sparring contest" for the fish, and was hardly the "charming display of affection" I interpreted it as.

And of course, I had no idea at the time that these fish could reach a size of 8-10 inches or more and live up to 25 years! I mean, a group of 5 of these in a 40 gallon community aquarium seemed just fine at the time! I wanted some! I mean, they were only like 2 inches long! T

hey'd "fit", right? Ahh, ignorance.

(pic by Jorn Kussender used under CC-BY S.A. 2.0)

Of course, what that fish did was further my efforts to petition my parents for a larger aquarium for my bedroom! The 5 gallon, metal frame tank I had since age 5 was no longer cutting it! Nope. I needed something larger. Time to step up to the big leagues. I knew instinctively that I could never successfully lobby for a 40 gallon aquarium, but I might just be able to make a case for a 15-20 gallon one!

Of course, it didn't hurt that my dad was a fish geek, with 3 aquariums full of fancy guppies  in the living room of our modest suburban home at the time. (A huge reduction from the 25 tank fish room he had in the garage when I was a toddler) He was the guy who got me into this thing- he could relate. He was the guy I could make my case to!

Of course, I did press my dad for the BIG tank (40 gallons)...and of course, he "counter-offered" with a more realistic 10 gallon tank. With a little more back-and-forth, and some "incentives" in place tied to a better grade in math, I was able to secure approval for a 15 gallon tank! Little did I know that these "negotiation exercises" would come in handy decades later, when I purchased my first home (yet another benefit of being a fish geek! You learn real life skills applicable to other stuff)! Each of us felt we got the best end of the deal: I got my larger tank- my mom and dad got little "Scotty" to shoot for an "A' in math! Win-win.

And of course, before I finally got the tank, there was a tremendous amount of research being done about all of the new, cool fishes I'd get! I had to keep a few of my favorites from the 5-gallon, like my Leopard Danios, the Corydoras aenus, and my small school of Glowlight Tetras! Other than those guys, it was a "clean slate!" And of course, I was able to negotiate, through a series of concessions, being able to keep the 5 gallon in operation after the new tank was in place! Yeah, my first foray into "MTS" (Multiple Tank Syndrome"), and I was only like 9.

This boded well for my future as a fish geek!

And of course, with the larger tank, I discovered that the accessories and equipment required had to be scaled up...And THIS is where my dad cleverly got me. Being an accountant, he wanted to teach me the value of money- and the lesson I was about to learn hit home: I had negotiated the tank, but the equipment I was to supply (unless I wanted some of his "hand-me-down" stuff from his old tanks, which I did not!).

And I learned the lesson that has served me well during a lifetime of fish-geeking: Larger aquariums require larger, more sophisticated equipment and accessories, and that adds to the expense. We all know this, but to a 9-year-old who wanted some Kissing Gouramis, it was an important lesson!

Well, it took a lot longer to accumulate all the gear I wanted for the new tank, and a lot more of my allowance than I wanted; a painful, but necessary tradeoff! I think this is when I really learned about discipline and patience in the hobby...staring at the shiny new, but decidedly empty aquarium in my bedroom, accumulating a little patina of dust as it awaited being outfitted for operation for several months.

And I didn't let those months go to waste.

I agonized over the stock list (something I still do today). I selected black gravel ('cause that was the COOLEST thing going at the time- and unfortunately, the priciest), an outside filter powered by an air pump (a LARGER, more expensive air pump than I had before, mind you), decided to go with live plants ( in my new black gravel- great decision, huh?), and painted the background of the tank a deep brown (hey, even then I had this affinity for that color, huh?).

Finally came the day everything was set up. Very exciting! Then to get some fishes in there. I remember going down to the LFS with my mom to get my first fishes- naturally, the "Kissing Gouramis" were at the top of the list. Of course, they were not in stock at the time, so I had to wait and get some others (I think I got some Red Swordtails and some Rasboras). Still was pretty excited, but really wanted those Gouramis!

And as the months passed and more and more fishes were added to my tank, the painful realization came that I was out of room for any new fishes- let alone, the Kissing Gouramis. Nonetheless, on a foray out to the LFS, I found some, and was ready to pull the trigger and finally grab the fish I had been coveting for almost 2 years at this point! Of course, the owner of the LFS, and old-school-type fish guy named Karl, was acutely aware of all of my fish purchases, as well as my tank. When I went to grab the Gouramis and fulfill my destiny- "tough love" set in...

Karl was quick to tell me, "Scott- your tank is pretty much full. Besides, you know those Kissing Gouramis can get too large for your tank.."

Damn! Thwarted. By my fish dealer! My source. I was done. Finished. Couldn't get those fishes. Not at his store. And quite frankly, not anywhere else, either- because I knew better...and so did my dad. Yet another valuable lesson for my fish-keeping "career."

You can't always get what you want.

Flash forward about 6 years...As a teen, I now had a 40 gallon breeder in my room (yeah, I pulled that one off!). I was looking for inspiration. I thought about some more fishes to add to the interesting mix I had accumulated: Loaches, "Sharks", Some Moss Green Tiger Barbs, Rasbora, Pineapple Plates, and some larger Tetras. The tank looked AWESOME! It was pretty full.  But I wanted more. Different. On a visit to the LFS,  I spied the fish of my youth...the Kissing Gourami!

And the stigma of Karl the owner being there to chastise me about my tank size and population was not a factor, as he had sold the store a couple of years back! I was footloose and fancy free- and damn rebellious, too!

Time to grab a group and fulfill my childhood fantasy!

And I was about to. then I noticed one of the Gouramis cowering in the corner of the dealer's tank, shimmying away. I knew what that meant. No go. Abort. Don't. And being the arrogant suburban, "I-want-it-now" teen with the New Wave haircut and accompanying attitude, I threw caution to the wind and pulled the trigger anyways: "Bag up these 5, please", I said, motioning to the seemingly healthy ones. They'd do fine, I reasoned. They weren't showing any signs of illness.

Quarantine. What's that?

Yeah, you know what happened: Into the tank the new Kissing Gouramis went. They looked just fine. I fulfilled my destiny, and at age 15, was finally about to have the fish I had coveted for almost a decade!

I earned this! I was stoked! 

That lasted all of about 48 hours, as every fish in the tank, including the Gouramis, began to clamp their fins, shimmy, and expire one by one. Along with my other fishes...No amount of "Rid Ich", "Quick Cure", or whatever other meds I had at the time did the trick- I had bet against the house and was felt a losing hand. Arrogance had gotten the best of me. 

I lost every fish but two.

Those damn Kissing Gouramis! THEY CAUSED THIS! THEY'RE A CURSE!

No, actually- my lack of judgement, impulsiveness, and youthful impatience caused it. My flaunting of some of the basic rules of aquarium keeping- to which I had been brought up to follow practically since I could walk-did me in this time.

A painful, humbling, invaluable lesson that I would never, ever forget. Even today, when I see a Kissing Gourami, I shudder just a bit, perhaps reminded of the painful lesson form that dark period in my fish keeping career. I came to call it "The Curse of The Kissing Gourami"- but really, it was no curse- it was the predictable end product of not doing what I knew I should have done- for tempting fate and throwing caution to the wind when it was not necessary...

Super painful. Unforgettable.

It's served me well. Very well. I've long since recovered from that painful reckoning, but the lesson that it taught me about patience, skepticism, fundamental- and, oh, yeah- quarantine of all new additions- has made me a much better hobbyist. So, I do still call it "The Curse of The Kissing Gourami", but I know now what it really was: A lesson. An awakening. A blessing, really. A factor in my growth and maturity, in both fish keeping and other facets of life.

I have never kept a Kissing Gourami since. Probably never will. But those five fishes which paid for my arrogance with their lives helped me in ways I couldn't even comprehend back then.

And to those of you, who've learned those painful lessons. Or have yet to experience the pain, I say to you- learn.

Grow. Listen. Don't forsake the fundamentals.

Stay patient. Stay humble. Stay inquisitive. Stay focused. Stay true to your best instincts.

And Stay Wet.


Scott Fellman

Tannin Aquatics





February 09, 2019


Accommodations, Compromises, Techniques, and Challenges...

Blackwater, botanical-style aquariums are certainly gaining a lot of attention I the hobby world at the moment. I'd really love to think of this not as some "trend", but as more of a methodology of aquarium keeping. Less of a "novelty"- more of an option.

Now, one of the best things about these types of aquariums is that there are no hard and fast "style rules." There are only Nature's "restrictions" and her limitations. That being said, and "best practices" aside, every situation, every tank, every nuance is unique, and this requires "customized" solutions for every aquarium. Sure, the methodology/strategy might be something which we can more or less "standardize"- but not the "formula."

As an example, the Rio Negro and its many tributaries provide us many different fishes that we love to keep in aquariums. The Rio Negro’s water is extremely poor in mineral content, with conductivity as low as 8 micro semions, and is extremely acidic, with pH’s ranging from 2.9 to 5.2. That's pretty damn acidic by aquarium standards, isn't it? How can you replicate water like that in your aquarium?

DO you want to?

Well, you'd start by utilizing RO/DI water and "conditioning it" with botanicals and such, which might only get you so far. There would likely be additional steps required, like the addition of acid solutions, different pH-reducing natural materials in your filter. And more detailed monitoring. And slightly different water-quality maintenance approaches. This stuff touches on the fringes of what a lot of us are comfortable doing.

And wouldn't it be easier to create and maintain these conditions with some compromising, like finding out the "average" of the pH and other parameters of the habitat you're trying to replicate and either going for it or perhaps, for the higher, easier-to-achieve higher limits of pH in the habitat, for example?

Even with a sort of "compromised accommodation" approach, you'd be providing your fishes with environmental conditions that are far more "realistic" than those typically provided in aquariums, right? Is there even a significant benefit to doing so? I believe so, but that's going to require some experimentation over time to prove.

That's what we need to do.

Yeah, easy for me to sit here and talk about, but it will require some work to back up this hypothesis!

And again, we've accomplished many amazing things without going to crazy into trying to more accurately replicate these natural conditions. yet, I just can't help but wonder what we'd accomplish if we go just that much farther. The examples which Nature provides us are many and varied.

We are getting better at this as a hobby/industry. Think about it. We can create more habitat-specific water parameters right now, because we have the means and way more accurate and "applicable" information about the natural habitat from which our fishes come from than ever before, and ways to monitor it that simply weren't available to the hobby years ago.

Couple this with better management of lighting, thanks to LED's, more controllable current, thanks to high-tech, electronically controlled pumps, and very accurate temperature control thanks to better heater/controller tech- and we're assured a continued progression towards more nature-specific captive environments for our animals.

Oh, and of course, there's the foods. Food is getting better than ever, and we're starting to see foods that contain a higher percentage of natural foods of many fishes- like aquatic insects, crustaceans, flies, etc. 


And you can state it enough- today's hobbyist is talented, intuitive, creative, smart, compassionate, and communicative in a way never before possible. The work being done is amazing!

It's a really exciting time to be a hobbyist.

The "next-level" breakthroughs will require just as much courage, effort, and creativity as they did in decades past, but the means to accomplish them are now at our fingertips.

And the potential payoffs- in terms of fish health, greater reproduction, and a more sustainable industry- not to mention, greater awareness of, and appreciation for the precarious nature of the wild habitats- will only assure us a brighter hobby future for ourselves, our fishes, and our children.

Don't shy from the challenge. Hit it head on! Accommodate, don't adapt.

Stay enthralled. Stay bold. Stay experimental. Stay creative. Stay relentless...

And Stay Wet.

Scott Fellman

Tannin Aquatics 


February 08, 2019


Boring consistency and the strange art of "pre-tinting."

Despite our rather unconventional approach to our aquarium hobby, we tend to employ some rather conventional practices...with our little twists, of course.  

One of the most important aspects of maintaining a blackwater, botanical-sty;e aquarium- or ANY aquarium, for that matter- is to keep the environmental parameters more or less consistent. Now, I'm not talking obsessively, insanely consistent- you know, not freaking out when the ph is .003 off from where it was yesterday...

No, I'm talking about stability within a range...

As we've discussed, fishes are remarkably resilient, tolerant animals if kept in a reasonably stable environment. And by "reasonably stable", I mean an environment in which the basic overall parameters (pH, alkalinity, nitrate, etc.) are not wildly fluctuating on a daily or even weekly basis (ok, you will see day/night pH fluctuations, of course). Rather, I'm referring to environmental conditions which stay within a rather narrow range, not in a constant drift towards one direction or another.

Fishes deal with changes in their environment on a continuous basis. Now, granted, the dissolution of materials and influx of new water by rain or whatever is mitigated by the sheer volumes of your typical wild rainforest streams and rivers, but the idea is that there are typically not sudden, radical environmental shifts that they contend with. Seasonal? Sure. But daily or weekly? Likely not typically.

One way we maintain a reasonably stable environment in our botanical-style, blackwater aquariums is to engage in...regular maintenance: You know, water exchanges, top-offs, etc. And of course, the usual centuries-old, tried-and-true techniques to keep our aquariums healthy: Careful stocking levels, conscientious feeding, and good old observation, and you're in a pretty good position! Nothing magic here.

The other is to do things which keep the unique blackwater environment stable and consistent. These practices consist of regularly adding and replacing botanicals as they break down, and engaging in some form of "pre-conditioning" or, as we love to call it- "pre-tinting" the makeup water that we use in water exchanges.

The idea of preparing makeup water for our aquariums is not new or earth-shattering, really. Planted tank enthusiasts, Discus breeders, and the reef community have been doing this for decades. I recall that I used to throw long-fiber peat moss into my water storage containers when I was a kid, back in my Killie days.

I called it "pre-tinting" of the water.

Basically, "pre-tinting" (our unique parlance) is utilizing some botanical materials to keep not only similar pH and alkalinity characteristics of the water consistent with those in your display tank- button keep the "visual tint" more or less consistent as well.

So I'll admit, as enamored with the idea of keeping consistent chemical parameters as I am, I'm probably equally as interested in the aesthetics. I know, that's super shallow of me..and sort of "immature", really, as it seems to be placing the looks over the chemical characteristics...

But here's the thing: I utilize RO/DI water. I know that my product water comes out of the unit at a consistent pH/alkalinity/TDS every time (provided I maintain/replace the membranes regularly, in accordance with manufacturer recommendations), and of course, confirmed with testing.

That being said, my approach is hardly "scientific"; shockingly more of an "art" than a "science" here.

Using RO/DO water gives me at least a fair amount of confidence about knowing what I'm working with, and at least what to expect, to a certain extent. I can more or less duplicate the conditions I want on a consistent . My 5 US-gallon plastic containers are "loaded" with 3 "medium-sized" Catappa leaves each week when I make the water. My water sits in the containers for one week before use. Some "tinters" use Alder Cones or Guava leaves, or if you're a "baller"- catalpa bark, or whatever...it's personal preference.

Now, again, it's not a perfectly scientific way, but it focuses on that main tenant of aquarium keeping that I treasure above almost all else: consistency. I do the same thing in the same way with the same stuff every single week. Yes, it's freakishly habitual, sort of inflexible, not exactly perfect- and undeniably geeky- but it works for me! 

Really well.

My aquariums - fresh, brackish, and reef- all rarely deviate to any real extent from a narrow range of water parameters that I choose to work with. In fact, they are almost rock-solid consistent. And I think that's made a big impact on the success I've enjoyed with my aquariums over the years. Not chasing "numbers"...Rather, pursuing consistency- and that starts with "pre-tinting" in our blackwater tanks.

Doing things like this the same way every time at least takes out one of the possible variables that can affect (in a negative way) your aquatic environment. When you're doing things exactly the same every week, it's easy to eliminate one of the possibilities if something does go wrong ("Well, I know one thing...It sure as hell ain't the water!"). Of course, you need to test your product water regularly to assure that parameters are not drifting out of your target range.

Oh, and by "target range"- I mean a range of a couple of points on the pH, etc. Like, I won't freak out if the tank is 6.4 and the water I'm adding is 6.5, although I would like to see it right on. It's not worth getting overly concerned about in my experience. look at the average over time. It's been the same with my brackish aquarium. The tank runs at a specific gravity of 1.010. I obviously target this in my makeup water, but occasionally, for wahtever reason, I might add a tiny bit more water to the container and the SG is 1.009 or so...I am not losing sleep over this.

Or fishes, for that matter!

IN the end, the idea of "pr-tinting" or "preconditioning your makeup water in some manner is just another practice to engage in in order to keep consistent environmental parameters in your aquariums. It's not revolutionary. It's not game-changing. And it's not an exact science, either. However, it IS a practice that I think many hobbyists could benefit from as they strive to maintain environmentally/aesthetically consistent, stable, aquariums.

Probably more than needs to be discussed on what is arguably a simple practice...but something worth thinking about, at least! A truly imperfect art...yet an impactful one, at that.

So, regardless of if you're keeping African rift lake cichlids, guppies, Discus, or fishes from the darkest blackwater swamps of Southeast Asia, the idea is the same: Do stuff that can get you there...even though it might be "boringly consistent."

Stay methodical. Stay consistent. Stay calm. Stay observant. Stay..."boring..."

And Stay Wet.


Scott Fellman

Tannin Aquatics 

February 06, 2019


Hitting the "pause" button...

It's an interesting thing in aquarium-keeping; we're almost never completely satisfied with our aquariums. I mean, sure we love our tanks; we're very satisfied with them- but typically, you'll almost always find at least something that we wish was better...

Yet, there are moments...

Have you ever just looked at your tank one day and thought to yourself, "This is IT! It can't get any better...I don't want to change anything...I just wish I could freeze things like they are now permanently..?"

You know, those moments when you catch glimpse of something in your tank. Or you just take in the entire tank and drop what you're doing to admire. Moments when you forget all of the algae problems you've had, the hardware failures...the disease outbreaks, etc.

Moments of pure awesomeness.

Moments when you want to just sort of "hit the pause button" and make the tank look like this forever.

I can't personally state that I've had those moments all that often...but I have had quite a few in a lifetime of fish-keeping. Perhaps they're random moments in time...times when you just did a water exchange and the fish are looking "just so" and the water is sparkling...yeah...moments.  Maybe it's when you look at your tan k"just so" and it reminds you of that underwater pic you saw from The Amazon.

Maybe it's when that pair of wild Apistos spawns. Or maybe, it's seeing that plant, which was struggling for months and months, finally starting to grow majestically.


Other times, it's simply the culmination of many months or years of "evolution" and growth.

A process.

And if you look at an aquarium as you would a garden- an organic, living, evolving, growing entity- 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

These moments...when you want to "hit pause" and simply savor. Are they the "finish line"- or just another moment in the journey?

IS there even a "finish line" to an aquarium? 

 I mean, to most aquatic hobbyists, what's more important? The end result, or watching the tank evolve over time? Do you covet rapid growth of plants and fishes, their daily appearance, or some other factor? And why? I suppose if I ask 100 hobbyists, I'll receive 100 different answers, but I am more curious about the prevailing attitudes among hobbyists about what constitutes a "moment." 

And a "great moment", in the context of an aquarium, is open to debate, right?

The reality is that an aquatic display is not a static entity, and will continue to encompass life, death, and everything in between for as long as it's in existence. What is it that really happens in a truly "mature" aquarium? Perhaps, there might be some competition between fishes, plants, or corals that results in one or more species dominating all of the rest...Or does diversity continue to win, with lots of different life forms eking out an existence in your artificial microcosm, just as they have managed to do for eons in nature?

Do they "bloom" or "express" themselves at various moments...or consistently "shine?"


Or perhaps, it's just that they connect with us on those truly amazing moments when you really want to savor them...to just "hit the pause button."

Savor them.

Stay motivated. Stay excited. Stay patient. Stay focused. Stay diligent. Stay enthralled...

And Stay Wet.


Scott Fellman

Tannin Aquatics


February 05, 2019


More water, more evaporation...more water...

We flirt with lower ph, lots of dissolved materials...organics, decomposition..."stuff" in the water. And keeping this "circus" of fluctuating parameters going is always a bit of a challenge. And of course, if you've kept aquariums for any length of time, one of the things that you've noticed is that they a re subject to evaporation.

Particularly, open-top aquariums, which yours truly both loves and offers for sale. Okay, some fish may jump if you do't secure the top somehow...but the tradeoffs make these types of tanks so worth it, IMHO.

Why should we care?

Well, for one thing, dissolved solids, minerals, organics, and salt( when present) do not evaporate. When evaporation occurs in your aquarium, the concentration of substances in the water actually increases as the water volume decreases.

In marine and brackish water aquariums, the specific gravity of the water can increase significantly as a result of evaporation, if fresh water is not added in an equal volume to replace it. This has health implications for the animals which reside in the aquarium.

Of course, in our botanical, blackwater aquariums, evaporation concentrates substances dissolved in the water, changing the environmental parameters over time. Now, we could argue, with our emphasis on experimentation and recreating the shifting water levels of say, African forest streams, rain puddles, and vernal pools, or Brazilian igarape, that water depth varies, and organic substances in the water concentrate, and that this is something our fishes can tolerate.

However, in my opinion, this would be a weaker argument for a closed system aquarium, because there is simply not the volume of flow-through, or even nutrient export processes occurring in our tanks that there happens in nature, even in all but the tiniest, most stagnant bodies of water (yeah, this little puddles where you find annual killies or wild bettas come to mind).

Now, these gross water-level changes typically occur over longer periods of time in natural systems than they do in the confines of a small aquarium. Rain, atmospheric conditions, runoff, and other phenomenon affect this. And in this instance, the words "tolerate" versus "thrive" are sort of at odds with each other, I think. 

All that stuff being equal, the one thing that I am a big believer in with every aquarium that I keep is environmental stability. Not the mindset of "pegging the pH at 6.3 without any fluctuation", mind you- No, rather, I proffer a stability within a small range. With evaporation, the "range" can become a lot broader, and the fluctuations can happen a lot faster than we'd like. In our aquariums with concentrations of botanicals, the ratio of pH-reducing/organic input-capable materials to water obviously increases as the water level decreases.

It's not one of those, "Ohmigod, my tank is going to crash if I don't do something about this right now!" sort of things, but dealing with regular evaporation in the botanical (or brackish) aquarium is an important consideration in the context of environmental stability. Stress from constant environmental fluctuation is a longer-term thing with fishes, yet it can lead to very tangible health issues over time if not addressed.

How much a given aquarium evaporates is based on a myriad of factors, such as the ambient humidity/temperature of the room it's kept in, the time of the year, how wide of an opening the tank has, etc., etc. There is no real "standard formula" of how much a given aquarium will evaporate in a specified amount of time. I've had 300 gallon aquariums that lost 4-5 gallons a week to evaporation, and much smaller tanks that lost that much in a day!

Obviously, in smaller aquariums, the affects of evaporation are more impactful and serious, and some means to address the issue should be considered above and beyond the routine weekly water exchanges.

The easiest way to deal with evaporation is to simply add more water (fresh water in the brackish or marine tank, as the salt concentration will increase as water evaporates). Kind of common sense, but something to think about, right? I'd go so far as to say that some regular "top-off" with freshwater is absolutely vital for the brackish tank, and fairly important for the lower pH, botanical/blackwater aquarium. And of course, we'll no doubt have many heated discussion on the merits of using "pre-tinted" tipoff water versus simply pure RO/DI water in botanical/blackwater tanks..

You can simply mark the side of your aquarium with a line in an inconspicuous place with permanent marker, and make sure that the water level never decreases below the line during normal operations. This simple and crude visual gives you a decent guide as to how much your water is evaporating on a regular basis. You can even get fancy and use the old standby math formula to determine how many gallons a given measure of water level loss represents (Sorry, metric users, I don't have the exact numbers for the conversion at the top of my head, but it's easy enough to do):

Multiply length by width by height of the tank and divide by 231.

Thusly, if you have a tank that's 48"x14"x20", the product is 13,440. Divide this number by 231 and you get 58.18 gallons. So, if you lost, say, 1/2" inch of height in the water column due to evaporation, that works out to 48x14x.5 = 336. Divide by 231 and you get 1.45 gallons. So...one half of an inch of water loss is equivalent to about 1.5 gallons of water.

Fairly significant, right?

I promise never to demonstrate math again in this blog. I think that is literally the only "formula" I've ever memorized (used to concoct "fantasy fish tanks" in my head for decades!), and I know some math whiz out there is going to be like, "Um, excuuuuuse meee- there is a better way to do this..." So forgive my remedial math skills!

But you get the idea, right?

The simplest way to combat the evaporation issue in the aquarium is to add a little water every day to "hold the line" in your tank. The visual marker makes it easy. However, this simple methodology only works if you're around to do it. Go away on vacation for a week or two, and you're unattended tank will definitely fall behind. Now, will this spell disaster? Likely not, unless you have an overflow weir in the aquarium or rely on a specific water level to keep pumps and heater submerged (and if there is little room for evaporation in this regard).

Yet, again, it's about stability. It's just a "thing" I have. Anything I can do to keep stability in my systems is a good practice. Good habits are always nice to acquire.

Or, you could automate it.

Yeah, I know- ME of all people- recommending automation. Scary.

I utilize a very simple, surprisingly reliable and efficient automated tipoff system. The one I use is the "Smart ATO Micro" system. It consists of a small LED optical sensor to detect water level (which can work in complete darkness), and a tiny little pump that can move water up to 6 feet. There are no moving parts to fail, which is a huge plus in this category of equipment. It's stunningly simple to use- in fact, it literally took me- "Mr. Mechanically Challenged", like 5 minutes or so to set up!

You simply locate the pump in a reservoir (which could be a small aquarium, big water jug, or other container used to hold your top-off water), attach a length of tubing (included) of sufficient length to reach your tank, and attach the tiny optical sensor via its magnet mount at the height you want the water level to remain at.

When the water level goes below the sensor height, the top-off pump is activated, and the micro-sized pump will dispense the exact amount needed to bring the water level back to the pre-determined level. Since it's so accurate, you'll see and hear the little pump going on multiple times throughout the day, simply topping off milliliters of water at a time to keep the level constant.

About the only maintenance you need to do is to keep the sensor clean (wipe it down once in a while with a toothbrush or similar), and make sure that you have sufficient water in your "reservoir" to assure top-off. Which you need to do, because I swear the low water level alarm is like designed to go off at 3AM...on a Monday night...seriously.

This little thing has changed my life, in terms of hassle, with the office blackwater/botanical aquarium you see on these pages. It's made the maintenance of constant water level a real snap, especially with our busy work/travel schedule and weekends and such, and I can't recommend it enough! 

There are a number of other excellent auto-topoff systems on the market, including the Tunze "Osmolator", which does an equally outstanding job, but is a bit more complex. I like "simple", and for our purposes, the unit I selected works great! I'm always looking for anything that can create stability in my system, and having a strategy (even if it IS just adding some fresh water to your tank every day via a reptile water dripper, or whatever...) is one of the easier practices that you can engage in to accomplish this.

So, we can look at evaporation as a problem, an annoyance, or simply part of the natural  world- something that we need to deal with to keep our systems running smoothly. It's just another aspect of aquarium keeping that everyone sort of knows about, but it's typically not addressed within the context of botanical-style aquariums.

Something to think about, huh?

It's about stability. Consistency. Diligence.

Stay on top of this. Stay observant. Stay careful. Stay methodical...

And Stay Wet.


Scott Fellman

Tannin Aquatics.



February 04, 2019


Recipes for distinction...Looking past the tint.

One of the interesting things I've noticed as we push out further and further in the botanical aquarium world is that hobbyists are looking at all sorts of wild aquatic habitats where leaves and botanical materials are found for inspiration- not just "the usual suspects" of blackwater streams, flooded forests, and such.

When you look, for example, at locales where many of our fave fishes come from, they're not typically "blackwater" habitats, yet they do have a lot of botanical materials present, like leaves, twigs, seed pods, and such. However, many of these habitats also have smooth stones, smooth fallen tree trunks, and fine/mixed sand, worn down by relatively swift currents.  

Many are turbid, detritus-and-sediment-filled locales, different in many respects from our blackwater systems, and radically different from the way many of us might perceive nature. 

Yet, they are incredibly alluring.

And then, there are shrimp habitats.

Many habitats where shrimp, like Neocaridina and Caridina and the like come from have clear water, sand bottoms, epiphytic algae and marginal/aquatic plants...and leaves. Others, are smoothly worn rock pools in little waterfalls, which have accumulations of algal films, occasional twigs and small branches, and of course, leaves. And the water is typically fairly clear, as opposed to "tinted."

If I were to do a dedicated Caridina aquarium (don't tempt me), specifically for my personal fave, the "Bee Shrimp" (Caridina cf. cantonensis), I'd definitely do a tank with lots of the aforementioned smooth stone; perhaps I'd use the ridiculously named, but very cool "Ancient Pagoda Stone"). My substrate of choice would be a Fien sand, and perhaps some of the "Marine biosediment" materials which I use in my brackish tanks.

For botanicals, I'd use a selection  of materials like Fishtail Palm Stems, Bamboo Leaves, a few Dregea Pods, Nypa Palm flowers, and maybe a smattering of Guava Leaves. Nothing that would tint the water too much, but stuff that adds to the look and function ( in this case, "recruiting" epiphytic algal growths and biofilms) of the aquarium.

If you were so inclined, I suppose you could include some aquatic plants, like Pogostemon erectuswhich, although not necessarily biotope specific, seem to represent (at least IMHO) some of the aquatic plants you might occasionally find in these habitats. I admit, not being a full-on aquatic plant guy, I haven't exhaustively or even super-enthusiastically researched what, if any species are typically found in these habitats- but there is information out there for sure.

But, yeah, I like the idea of some algal-covered stones and accumulations of leaves and botanicals. Simple, yet alluring- and biotopically "on point", I think.

That's how I'd do it. 

I think that this is a bit of a departure from the usual-plant-dominant aquariums in which so many enthusiasts seen to keep their shrimp. I may be a little out of touch, but I see a tremendous amount of shrimp tanks that are essentially beautiful planted aquariums. Nothing wrong with this at all, but I think that really taking a look at their natural habitats and working from there yields yet another very attractive look that you have to really execute to appreciate.

One of the reasons why I"m so in love with Rachel O'Leary's recent shrimp tank video (besides the fact that it features our botanicals!) is that she properly emphasizes using botanicals in them...

Indeed, she is an avid believer (like me) that you don't always need to use botanicals to create blackwater aquariums. Her shrimp tanks have plants to a certain degree, but botanicals rightfully take center stage- doing what they do in nature- accumulating biofilms and epiphytic growth, and providing grazing opportunities for the shrimp.

I love how we can always seem to turn to Nature to 

I mean, there are even locales in African Rift Lakes where you might find materials like leaves and some branches and plant parts accumulating over mud or sediment. In fact, these areas are host to a variety of different fishes with unique life habits.  Obviously, the water is extremely hard and alkaline- and clear- in these habitats, influenced more by geology than wood or leaves or other materials, yet you will see the presence of botanical materials in there. 

I think it's a matter of selection. A matter of looking at what you actually see in Nature and interpreting it for our aquariums. 


A lot of what you'll see in many wild habitats is a bottom consisting of sediments, and, and a matrix of leaves and branches covered by epiphytic algal growths. And again, the water is not necessarily brown, or even slightly tinted. In fact, it's often more "turbid" than "tinted." Even in our beloved Amazonian region, areas like the Pantanal often have sandy bottoms covered with leaves and branches...and clear, or slightly turbid water.

Natural habitats where many of our fishes hail are perhaps not even all that "conventional" by aquarium/aquascaping standards. Again, a tangle of twigs, branches, and leaves covered in sediment and algal films is not everyone's idea of "attractive" for aquarium purposes- but it's very, very authentic. And I think it's one of those things that you have to actually execute to appreciate.

Like many of the aquariums we proffer here, you'll need to make some mental shifts to enjoy this look. You'll likely face the usual criticisms from dark corners of the Internet, criticizing your use of alga and detritus-filled hardscape as "the result of lackadaisical husbandry practices" and "low standards of cleanliness..."

Been there, heard that. Right?

And sure, perhaps you will have to point to videos and photos of the many wild habitats which reflect these features in order to "vindicate" yourself among your peers.

Maybe you'll change some minds. Maybe you'll unlock some secrets.

Can you handle turbidity and sediment? CAN you? 🤔

It's okay to "look past the tint" and into the future...

Stay resourceful. Stay interested. Stay bold. Stay creative...

And Stay Wet.


Scott Fellman

Tannin Aquatics 




February 03, 2019


The fruits of our labors?

We've talked so much about the idea of using dried botanical materials as "stand- ins" for all sorts of fruits and plant materials which hare found in rain forest and other tropical aquatic habitats. We love the idea of them serving as not only "habitat enrichment" vehicles, but as supplemental food sources for many of the fishes and shrimps that we keep in our aquariums. 

Now, hardcore biotope enthusiasts have discussions about finding the exact types of fruits as are found around these forested locales, and I love them for it. However, the reality at the present time is that many of these fruits are either not available outside of their native regions, or have not been studied.

Many, not all.

Here's a list of Amazonian fruits to get those of you who are adventurous, started:

Maracuya- "Passion Fruit"

Bacaba- a fruit from a palm tree

Cupuazu- a relative of Coca

Aguaje- another palm-derived fruit (from the "Moriche Palm)

Cocona- a large berry from a forest shrub


(Agueje- from the "Moriche Palm"- image by Didier Descouens, used under CC BY-SA 3.0)

So where does that leave those of us who love the idea of utilizing these types of things in our tanks? We need to either find them, or locate suitable "surrogates"

It's not impossible to find out this information...we just need to dig deeper and deeper into the scant, esoteric scientific information that is out there on such matters.

I don't think that either is a bad thing!

I think botanicals can play a big role in helping to recreate, at least in some part, this unique aspect of our fishes' environment.

Many of the botanicals that we offer at Tannin were selected and curated specifically with that intention and concept in mind. The idea of utilizing "facsimiles" of materials found in the wild habitats of our fishes is a good one, IMHO. We didn't just look at a bunch of dried stuff and say, "Aha! That's good to sell!" Nope, the idea was that each one of the things we offer could serve as a "stand-in" for the "generic" materials which are found in the wild habitats of our fishes.

Yes, stuff from trees falls into the waters, and is swept by currents downstream, where it influcenss the aquatic ecology. Or, materials from trees fall to the dry forest floor, where they become part of the aquatic environment when the rainy season overflows surrounding streams and inundates what was once a rich, terrestrial habitat.

Think about it. We don't simply toss leaves, seed pods, etc. into our tanks just to tint the water. We have learned that these materials provide many other "functional benefits", such as fostering biofilms, fungi, crustacean growth, fish hiding  and spawning sites, etc.

Thinking about how stuff accumulates on the rain forest floor or falls directly into the water from trees is a key component to grasping this concept and aesthetic. Now, it's truly not "rocket science" to think about stuff falling from the trees, but when you contemplate the idea, you begin to think about the "randomness" of the process. Botanical materials like leaves, seed pods and the like fall off trees seasonally, or as a result of wind and weather events, so there is no specific "pattern" of accumulation, except, perhaps that more materials tend to fall off trees during weather events.

In general, fish, detritus and insects form the most important food resources supporting the fish communities in both wet and dry seasons, but the proportions of invertebrates fruits, and fish are reduced during the low water season. Individual fish species exhibit diet changes between high water and low water seasons in these areas...an interesting adaptation and possible application for hobbyists?

Well, think about the results from one study of gut-content analysis form some herbivorous Amazonian fishes in both the wet and dry seasons: The consumption of fruits in Mylossoma and Colossoma species was significantly less during the low water periods, and  their diet was changed, with these materials substituted by plant parts and invertebrates, which were more abundant.

Fruit-eating is significantly reduced during the low water period when the fruit sources in the forests are not readily accessible to the fish. During these periods of time, fruit eating fishes ("frugivores") consume more seeds than fruits, and supplement their diets with foods like as leaves, detritus, and plankton. Interestingly, even the known "gazers", like Leporinus,  were found to consume a greater proportion of materials like seeds during the low water season.

Now, during the wet season, mud and detritus are transported via the overflowing rivers into flooded areas, and contribute to the forest leaf litter and other botanical materials, coming nutrient sources which contribute to the growth of this epiphytic algae, which helps sustain fishes during the dry season!

During the lower water periods, this organic layer helps compensate for the shortage of other food sources. When the water is at a high period and the forests are inundated, many terrestrial insects fall into the water and are consumed by fishes. In general, insects- both terrestrial and aquatic, support a large community of fishes.

So, it goes without saying that the importance of insects and fruits- which are essentially derived from the flooded forests, are reduced during the dry season when fishes are confined to open water and feed on different materials. 

It's interesting to contemplate designing a biotope or other aquarium around feeding, an important but often overlooked aspect of fish behavior (when it comes to tank design, that is! With a little research, planning, and a lot of experimentation, what interesting discoveries can be made? What breakthroughs await?

Combining our much evolved expertise in fish feeding with our love of aquascaping seems almost a natural combination, doesn't it?

What secrets will you unlock? The literal "fruits of our labors!"

Stay on it.

Stay curious. Stay diligent. Stay resourceful...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


February 02, 2019


Rain, botanicals, and the "365 Dynamic..."

As a lifelong resident of Los Angeles, when it reads here, for some reason, it becomes that biggest news around. You'll literally have people calling in radio stations, breathlessly exclaiming, "And there's just like tons of rain coming down here in Santa Monica!" (or insert your fave L.A. suburb). We freak out about it. Avoid driving in it, and generally celebrate it.

And that's how it should be, IMHO!

It's transformational, essential for our existence...and for the continued existence of many of the fishes we love, as well as the habitats from which they come.

(Pic by David Sobry)

And specifically, what interests me about rain is what happens when it rains in the wild habitats of our fishes, and how they behave. How do their habitats change with the coming and going of the rains?  What happens to the fishes during the rainy season?

I know, you're gonna say, "They get wet..." 

Look, no one likes a smartass, okay? 😆 Especially a fellow smartass!

Well, what happens in the "rainy season" in say, the Amazon Basin? (like, why did you know that I'd start there? Hmm?)

A lot of things, really.

The wet season in The Amazon runs from November to June. And it rains almost every day.

And what's really interesting is that the surrounding Amazon rain forest is estimated by some scientists to create as much as 50% of its own precipitation! It does this via the humidity present in the forest itself, from the water vapor present on plant leaves- which contributes to the formation of rain clouds.

Yeah, trees in the Amazon release enough moisture through photosynthesis to create low-level clouds and literally generate rain, according to a recent study published in the Proceedings of the National Academy of Sciences (U.S.)!

That's crazy.

But it makes a lot of sense, right?

That's a cool "cocktail party sound bite" and all, but what happens to the (aquatic) environment in which our fishes live in when it rains?

Well, for one thing, rain performs the dual function of diluting organics, while transporting more nutrient and materials across the ecosystem. What happens in many of the regions of Amazonia - and likewise, in many tropical locales worldwide-is the evolution of our most compelling environmental niches...

The water levels in the rivers rise significantly- often several meters, and the once dry forest floor fills with water from the torrential rain and overflowing rivers and streams. In Amazonia, it means one thing:

The Igapos are formed. 

All of the botanical material- fallen leaves, branches, seed pods, and such, is suddenly submerged. And of course, currents re-distribute this material into little pockets and "stands", affecting the (now underwater) "topography" of the landscape. Leaves begin to accumulate. Tree branches tumble along the substrate  Soils dissolve their chemical constituents, tannins, and humic acids into the water, enriching it. Fungi and micororganisms begin to multiply, feed on and break down the materials. Biofilms form, crustaceans reproduce rapidly.  Fishes are able to find new food sources; new hiding places..new areas to spawn.

Life flourishes.

So, yeah, the rains have a huge impact on tropical aquatic ecosystems. And it's important to think of the relationship between the terrestrial habitat and the aquatic one when visualizing the possibilities of replicating nature in your aquarium in this context.

This is huge, important stuff that any real "natural aquascaping" enthusiast needs to get his/her head around. 

It's an intimate, interrelated, and "codependent" sort of arrangement!

And of course, I think we can work with this stuff to our fishes' advantage!

We've talked about the idea of "flooding" a vivarium 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.

The time to play with this concept is now!

Sure, you'd need to create a technical means or set of procedures to gradually flood your "rainforest floor" in your tank, which could be accomplished manually, by simply pouring water into the vivarium over a series of days; or automatically, with solenoids controlling valves from a reservoir beneath the setup, or perhaps employing the "rain heads" that frog and herp people use in their systems. This is all very achievable, even for hobbyists like me with limited "DIY" skills.

You just have to innovate, and be willing to do a little busy work.

Think about the possibilities here! It's crazy!

As the display "floods", the materials in the formerly "terrestrial" environment become submerged- just like in nature- releasing nutrients, humic substances, and tannins, creating a rich, dynamic habitat for fishes, offering many of the same benefits as you'd expect from the wild environment.

Recreating a "365 dynamic" environment in an aquatic feature would perhaps be the ultimate expression of a  biotope aquarium- Truly mimicking the composition, aesthetics- and function of the natural habitat. A truly realistic representation of the wild, on a level previously not possible.

Of course, I have no illusions about this being a rather labor-intensive process, brought with a few technical challenges- but it's not necessary to make it complicated or difficult. It does require some "active management", planning, and diligence- but on the surface, executing seems no more difficult than with some of the other aquatic systems we dabble with, right?

And utilizing botanicals is just the start, really. 

Yes, you'd have to make some provisions for "relocating" the terrestrial inhabitants of your system, like frogs, to "higher ground" (i.e.; another vivarium) during the "wet season"...or your could create a paludarium-type setup, with both a terrestrial and an aquatic component simultaneously, and not sweat it.

The possibilities for education, creative expression, and flat-out experimentation are really wide open here. A great way to examine and appreciate the cycle of life for many organisms!

Hey, wouldn't this be a cool way to play with some  annual or bottom-spawning killifishes?  Yeah! 

It's just another example of looking at Nature, then thinking of ways to really incorporate her function into our aquatic displays. 

In this world of decomposing leaves, submerged logs, twigs, and seed pods, there is a surprising diversity of life forms which call this milieu home. And each one of these organisms has manages to eke out an existence and thrive.

A lot of hobbyists not familiar with our aesthetic tastes will ask what the fascination is with throwing palm fronds and seed pods into our tanks, and I tell them that it's a direct inspiration from nature! Sure, the look is quite different than what has been proffered as "natural" in recent years- but I'd guarantee that, if you donned a snorkel and waded into one of these habitats, you'd understand exactly what we are trying to represent in our aquariums in seconds!

We also happen to like the way it looks, of course! 

Let's get to it.

Right now, however, I'm just gonna look out the window and enjoy the rain for a bit. Did I mention, it's raining here in L.A., and...

Stay inspired. Stay intrigued. Stay curious...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

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