Habitat enrichment, redoux

The other day, I performed my weekly water change on the 50 gallon aquarium in our office. As part of the routine, I take a soft-bristled brush to the surfaces of my botanicals which might occasionally develop a slight build up of algae. Interestingly, I find myself doing this less and less as the months go on in a given aquarium. Based on my experience with botanical-themed systems, the blooms of biofilms and algae that one might encounter early on tend to dissipate after a couple of months, only making sporadic, transitory appearances, if that.

Anyways, I noticed a bit of algae on a "Terra Sorrindo" pod that I've had in the aquarium since its inception last November, and I reached for the piece and removed it from the water to give it a gentle scrub-down...and the 'Sorrindo promptly disintegrated in my hands! Another botanical did it's job, gradually releasing tannins and humic substances over the months, until finally decomposing back into its constituent parts. The essence of what we call "habitat enrichment"- imparting beneficial substances and materials to the overall environment- in this case, the aforementioned tannins, humic substances, and ultimately, its inert outer shell. Fishes foraged upon its surfaces, shrimp consumed its lignin-rich tissues, and microorganisms flourished on its matrix of interstitial surfaces.

The end of this botanical's "service" life was symbolic, in a way, of what takes place in our aquariums: Fungi, bacteria algae...indeed, the water itself all conspire to erode, degrade, and ultimately, decompose these materials...a real cycle of life. As I continued with my weekly maintenance, I siphoned out a few stray pieces of broken-down leaves and added some new, colorful ones (one of my favorite things!), which is sort of like "re-scaping" the aquarium every week.

It serves the twofold purpose of keeping the water "tinted", the pH more-or-less consistent, and the look and vibe of the tank "fresh"- so similar to what goes on in nature, when old leaves break down, and new ones fall into bodies of water to take their place.

New leaves are sort of a biological/chemical "shot in the arm" for a botanical aquarium.

Speaking of leaves (what a smashing segue, huh?), we receive a lot of questions, in the course of our daily operations, from hobbyists who inquire about adding leaves of various types that they've collected in their local area, wondering if they can use them in their aquarium. It's a very good question, and one which deserves a good answer!

My response typically conservative, admonishing them to "qualify" the leaves first ( i.e.; collected from a "clean" area, free of pesticides, fertilizers, or environmental pollutants), and to make sure that they are using naturally-fallen leaves from deciduous trees. The "naturally-fallen" part is really important.

Why? When the seasons change and trees drop their leaves, much of the material bound up in the leaves' tissues, such as sugars, and more prominently, nitrogen and phosphorous, is essentially "re-absorbed" back into the tree itself before they drop, via chemical pathways and processes. The trees use all of that good stuff to sustain themselves over the long-term after seasonal changes. (winter in temperate climates, and the dry season in tropical climates)

Green leaves, which have not naturally fallen, still contain the bound-up nitrogen, sugars, and other substances in their tissues which the tree utilizes for energy. And when you use those leaves in your aquarium- guess what? You're releasing all of those bound-up sugars and nitrogen into your water, thus increasing nitrate levels and bioload in your tank- something most hobbyists like to avoid. We want the leaves for their tannins and humic acids, not for a cocktail of sugars, nitrogen, and phosphorous...so avoid using green leaves in your aquarium in your leaf litter bed!

On occasion, a customer may comment about the leaves we send them, remarking that they look pretty dried...and I respond by telling them that this is the whole point! You want to utilize, clean, dried leaves that have been collected after they have naturally fallen. Besides, the leaves look amazing, displaying beautiful and varied colors, after they have naturally fallen, providing not only environmental benefits, but a huge aesthetic component as well.

And a diversity of leaves is important, in my opinion, because not only are you getting a nice "aesthetic" benefit, but I feel that varying leaves impart varying levels of tannins and humic substances to the water...Yes, somewhat anecdotal on my part, but I believe I am correct in this assumption, as my personal experience and that of other "tinters" has shown. A nice mix of Catappa, Guava, Loquat, Magnolia, and Jackfruit is amazing to look at.

And again, there is always that question about preparation...Does boiling the leaves remove too much of the tannins and humic substances that you want from the leaves? I'd say that boiling the leaves does. Steeping them a bit in boiling water (say, 10 minutes), however, will release some of the initial burst of tannins found in their tissues, and will help them sink more rapidly, while leaving much of the desired tannins intact over the longer term, in my experience.

Over the last few months, I've simply been rinsing my leaves, then soaking them overnight in room-temperature RO/DI water before using in my aquariums. I've had no issues. As a business owner and responsible aquarist, I opt to recommend the most conservative course of action, hence my recommendations all over the site to steep them in boiling water. Probably more of a habit than a necessary practice for me...That being said, if you are comfortable with "rinse and drop" right from the bag, more power to you! I've done it numerous times without any problems at all.

In the end, utilizing leaves and other botanicals in your aquariums is all about enriching your aquatic environment, providing your fishes with extremely beneficial tannins and humic substances which have scientifically proven health benefits, and adding a "matrix" of material to support biological activity and production of natural food sources. "Habitat enrichment" in the truest sense.

And, there will be a lot more about the benefits of botanical-style aquariums coming to he forefront soon. I recently became acquainted with another remarkable hobbyist who has done extensive research on the concept of utilizing leaves and botanical materials on the basis that they are a rich source of humic substances, which offer absolutely amazing health benefits for fishes, borne out by some remarkable peer-reviewed lab research. I'm coercing him into writing a guest blog on this fascinating topic in the coming weeks!

We are at an exciting time in the aquarium hobby, particularly as it pertains to creating more "natural" conditions for our fishes. The use of botanicals in the aquarium, although not a new practice, is becoming more and more understood and appreciated for a wide range of benefits, not just because they look cool (Which is a pretty good benefit, IMHO)! Rather, we're at a time of great experimentation, discovery, and even more important- sharing of ideas in the hobby. With so many talented hobbyists playing with botanicals more and more, the varied long-term benefits to our fishes will be better and better understood, for the benefit of all!

So stay engaged. Stay curious. Stay experimental.

And Stay Wet.

Scott Fellman

Tannin Aquaitcs




Scott Fellman
Scott Fellman


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