Every sunken branch. Every single leaf...

One of the most compelling things about creating a botanical-style, blackwater aquarium is that the very process of using leaves, seed pods, and other natural materials is in essence, replicating nature.

As  we've discussed many times, numerous tropical habitats are flooded forest floors, or tiny streamiest which may be seasonally dry. Large water level fluctuations subject many of these forest areas to constant shifts between terrestrial and aquatic environments. This fact should be something we take into account in our aquascaping. When attempting to replicate an inundated forest floor or seasonal stream, think about the surrounding plant materials which are found when the environment is in a "terrestrial phase."

As we know, there are numerous materials which, once the water reach them, have significant influence on not only the chemical parameters of the water, but the physical makeup of the underwater habitat. Accumulations of materials like seed pods and leaves create territories and places for fishes to inhabit, shelter, and spawn among. In these transient habitats, materials like leaves and seed pods are important, as they decompose at varying rates, providing food sources for numerous animals during the inundation periods.

So, when you're attempting to replicate such an environment, consider how the fishes would utilize each of the materials you're working with. For example, leaf litter areas would be an idea shelter for many juvenile fishes, catfishes, and even young cichlids to shelter among. Submerged branches, larger seed pods and other botanicals provide territory and areas where fishes can forage for macrophytes (algal growths which occur on the surfaces of these materials). Fish selection can be influenced as much by the materials you're using to 'scape the tank as anything else, when you think about it!

And there are numerous life forms which are found on these materials as well, which we never really consider, yet are found in abundance in nature and perform vital roles in the function of the aquatic habitat.

Perhaps most fascinating  and rarely discussed in the hobby, are the unique freshwater sponges, from the genus Spongilla. These interesting life forms attach themselves to rocks and logs and filter the water for various small aquatic organisms, like bacteria, protozoa, and other minute aquatic life forms.  

(A BIG freshwater sponge! Image by Jomegat, used under CC BY-S.A. 3.0)

Unlike the better-known marine sponges, freshwater sponges are subjected to the more variable environment of rivers and streams, and have adapted a strategy of survival. When conditions deteriorate, the organisms create "buds", known as  "gemmules", which are an asexually reproduced mass of cells capable of developing into a new sponge! The Gemmules remain dormant until environmental conditions permit them to develop once again!

To my knowledge, these organisms have never been intentionally collected for aquariums, and I suspect they are a little tricky to transport (despite their adaptability), just ike their marine cousins are. One species, Metania reticulata, is extremely common in the Brazilian Amazon. They are found on rocks, submerged branches, and even tree trunks when these areas are submerged, and remain in a dormant phase in the aforementioned gemmules during periods of desiccation!

Now, I"m not suggesting that we go and collect sponges for aquarium use, but I am curious if they occur as "hitchhikers" on driftwood, rocks or other materials which end up in our aquariums. When you think about how important sponges are as natural "filters", one can only wonder how they might perform this beneficial role in the aquarium as well! Have any of you encountered one before in your tanks?

Think about the possibilities which are out there, under every leaf. Every sunken branch. Every rock.

Stay creative. Stay curious. Stay observant. Stay excited.

And Stay Wet.


Scott Fellman

Tannin Aquatics 






Scott Fellman
Scott Fellman


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