"Managed Evolution": A look at a year or so in the life of our office blackwater aquarium

One of the things we've talked about a lot here is how botanical-style aquariums, perhaps more so than many other "style" of aquarium, lend themselves to "editing", or more properly, "managed evolution" the longer they're in operation. Since we're dealing with materials such as leaves which decompose, and seed pods and such which soften and slowly change form, the opportunity to replace/supplement/remove them is almost a "constant." Sure, you can simply leave everything alone, and let the leaves disintegrate to nothing, but ultimately, you'll want to replace them. Not only will it keep the level of "tint" consistent, but it gives you the opportunity to create an evolving/varying habitat, just like nature. And of course, it looks kinda cool, too!

I thought it would be interesting to sort of look back at our office aquarium, a 50 gallon (200L) tank, to which we applied this "managed evolution" style, and examine it as a sort of "case study", if you will.

I remember when starting this aquarium, we decided that we'd create the "foundation" of the tank with a few pieces of Manzanita wood, some heavier botanicals, with a few river stones, which would function as the "permanent" part of our 'scape.

Interestingly, I initially wanted to use the botanicals without the rocks, but realized two things: without the stones, it sort of lacked something, and the fact that rocks are often found in the environments I was modeling my tank after. This was my very first adjustment, and made a lot of sense, and continues to as the microcosm evolves. One thing I did want to do was run the system with the heavier botanicals for a while before adding lightweight materials and leaves. This gave the system ample time to run in, and for the heavier "Savu Pods", "Heart Pods", "Terra Sorrindo", and such sort f soften and break in a bit before moving on to the more "transient botanicals, such as Banana Stem Pieces, Coco Curls, etc. 

One decision I made, which I would NOT do the same again, was to cure the Manzanita in the display. I really wanted each material used to impart as much tannin and other humic and organic material into the system as possible before fish were ever present, so that was sort of my rationale. Really, in the end, what it DID was recruit a lot of biofilms, some bacterial cloudiness for a time, and take a long time to saturate and sink in place. Next time, I'd soak the wood for a few weeks in an external vessel of water. The biofilms were no issue, but without any "consumers" in the tank, it was a combination of scrubbing, manual removal, and time that got through the worst of it.

I purposely employed as many botanicals as possible with minimal preparation on them, for the expressed purpose of them imparting as much material into the water as possible. Not only was this sort of a commitment to the botanical-heavy theme of the aquarium, it was functioning as sort of a real-time laboratory, if you will, for seeing the effects of an influx of a larger quantity of these materials in a new tank. The findings from this tank helped further evolve our methodologies and recommended preparation/application procedures which we discuss on our website and elsewhere on a constant basis. We needed to play with "worst case" scenarios to know the BEST way to work with these products, and pushing it in our own tanks is always the best thing to do. fter the tank had cycled and we began to notice stable readings on the major environmental parameters that we monitored, we began to add some fishes; the initial characin inhabitants were the rather touchy "Rummynose Tetras!"

We also decided to add some Apistos that we had for a while in our tank at Unique Corals, which were from my go-to Apisto guy, William Garden. They proved hardy enough, and (gulp), I felt it a worthy experiment to add some somewhat touchy fishes to this newer tank (it had been running about a month without any other fishes) to really see how well they would do in this environment. I put my money where my mouth is with my experiments!

As things progressed, the tint in the water was increasingly noticeable, the biofilms started to wane a bit, and the fishes continued to thrive we began to evolve the tank a bit more, with different botanicals, more fishes, and the initial leaves starting to show up.

This was an important time. It sort of was analogous to an igarape in the Amazon region, which fill with water after a deluge, initially submerging the tree roots, branches, rocks, and harder botanical items which accumulated on the forest floor during the dry season. The leaves are not there accumulating in great numbers just yet, having been swept away in the initial inundation, and are gradually starting to accumulate as the waters remain.

We found that the guava leaves, long our favorite, offered a really good aesthetic compliment to this tank, and began to make extensive use of them, along with the "required" catappa leaves, of course!

And the tint. Ahh, the tint was really beautiful now...A rich, deep golden brown color that really popped the colors on our fishes. The environmental parameters began to fall in a very tight pH range, and nitrate and phosphate virtually undetectable...At about 4 months, the tank really began to hit it  stride and sort of never looked back. we got into a regular "rhythm" of adding and removing leaves as needed, and would pop out a fe botanicals here and there to try new ones...Again, sort of like what happens in nature, when new materials are swept into, or fall into the waters as the season change. 

At one point, we really had a lot of leaves and botanical in there, to sort of simulate a "peak" time of year when the most leaves began to accumulate. I love taking weird angle shots of my tanks during water changes, and this tank is a joy for that!

At about the one year mark, the tank just sort of had an "aged", natural look. Everything had a nice "patina" to it, and looked extremely "organic", as if it "evolved" as a whole. And the scent...in an open top tank of this size, you'll get his wonderful, earthy, "garden-after-a-rain"-type scent that is invigorating and relaxing. The tank was becoming what all blackwater tank are- a true sensory delight on many levels.

I had for a long time though about adding some plans to the tank...just a few, partially as a "proof of concept" for myself to see if they'd do okay i the environment, and partially because i had a vision for how they'd look in the tank. About this time, I was speaking at a conference in the Midwestern U.S., in which the great aquascaper, Luis Navarro (now with Aquarium Design Group) was present. He and I spent a good amount of time talking about blackwater environments and plants, and he shared with me photos he took while exploring these environments in Mexico, which had wonderful plant growth...I was hooked. Generous fish geek that he is, Luis insisted on sending me a few cuttings of a plant that he felt would be really cool- Polygonum sp. "kawagoeanum", and he was right. It IS a cool plant!

I decided to approach the planting of these guys in a different manner than most hobbyists would: Just plunk them down in between the Manzanita and let 'em shoot for the surface, not really "pruning" them in any way...letting nature do it's thing. 

The plants have really added a new dimension to the environment, and compliment the botanicals so well. It's a really lively, yet relaxing scene...With complex texture, color, and life. With the additions of new leaves of different varieties, and the ability to change the colors slightly via the leaves as I choose, the tank has become an earthy, ever-evolving palette.

With different lighting effects hitting the tank at different times of day, natural light supplements the consistent LED lighting for amazing, changing looks on almost an hourly basis. It's incredibly relaxing for us to look at this tank in our office, and actually, very inspiring- as we share with you our love of the ever evolving, always-enthralling blackwater, botanical-themed aquarium environment.

By "managing the evolution" of the tank, adding and removing various botanicals, we're effectively able to "makeover" various aspects of this display without substantially changing the entire scene. This unique benefit of the botanical aquarium will hopefully resonate with many of you who are looking for a unique aquarium to work with for your next project.

We hope you enjoyed this look at the first year or so in the life of our office aquarium as much as we've enjoyed sharing it with you...and we hope that you embark on your own blackwater/botananical-themed aquatic journey soon!

Keep evolving.

Stay intrigued. Stay creative. Stay excited.

And Stay Wet.

Scott Fellman

Tannin Aquatics 

Scott Fellman
Scott Fellman


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