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