Looking for a new biotope to model? How about a floating litter bank habitat?

[bekateen]

On the heels of this post (Re: Reproductive biology of Rineloricaria uracantha) which discusses hanging tubular wood for Rineloricaria spawning in midwater, I give you another older paper which takes advantage of the "upper waters" of your aquarium - No more does your catfish tank need to be a bottom-dwellers-only habitat! (of course, this won't be a new concept to long time catfish keepers, but maybe for our newer members)

Carvalho, Lucélia Nobre, Fidelis, Luana, Arruda, Rafael, Galuch, André, & Zuanon, Jansen. (2013). Second floor, please: the fish fauna of floating litter banks in Amazonian streams and rivers. Neotropical Ichthyology, 11(1), 85-94. https://doi.org/10.1590/S1679-62252013000100010

http://www.scielo.br/scielo.php?pid=S16 ... ci_arttext

ABSTRACT

Floating litter banks are an ephemeral habitat consisting of branches, twigs, flowers, seeds, and fruits that are trapped on the stream water surface by a variety of retention mechanisms. These heterogeneous materials form a deep layer of dead plant matter that is colonized by a variety of organisms, including fish that forage on the aquatic macroinvertebrates found in this unique habitat. In this study, we aimed to characterize which fish species occupy the floating litter banks and their trophic characteristics, as well as determine if fish assemblage composition and species richness can be predicted by the size of the floating litter banks. Fish sampling was conducted in five rivers located in the Amazon basin. Of the 31 floating litter banks sampled that contained fish, 455 individuals were recorded and were distributed within 40 species, 15 families and five orders. Siluriformes were the most representative order among the samples and contained the largest number of families and species. The fish fauna sampled was mainly composed of carnivorous species that are typically found in submerged litter banks of Amazonian streams. The fish assemblage composition in the kinon can be predicted by the volume of the floating litter banks using both presence/absence and abundance data, but not its species richness. In conclusion, kinon banks harbor a rich fish assemblage that utilizes this habitat for shelter and feeding, and may function as a refuge for the fishes during the peak of the flooding season.

• Key words: Ephemeral habitats; Fish assemblages; Insectivores; Lotic systems; Trophic structure

A lot of aquarium-relevant fishes were found in these rafts. For a complete list (cichlids, tetras, etc.), see the table. I've reproduced the list of catfishes here (but I did not update scientific names below - I copied from the paper):

Auchenipteridae

• Parauchenipterus galeatus

Doradidae

• Acanthodoras spinosissimus

Cetopsidae

• Denticetopsis seducta

• Helogenes marmoratus

Heptapteridae

• Brachyglanis microphthalmus

• Nemuroglanis pauciradiatus

• Phenacorhamdia
  sp.

Loricariidae

• Acestridium discus

Trichomycteridae

• Trichomycterus hasemani

• Trichomycterus johnsoni

Pseudopimelodidae

• Batrochoglanis raninus

• Batrochoglanis villosus

• Microglanis
  aff. poecilus

• Microglanis sp.

[Bas Pels]

While such a tank would be very intersting, the problem would be the decaying organic matter.

That is, the constant worsening of water quality. In nature the system is large, our tanks are relatively small, even a large one.

[dw1305]

Hi all,

While such a tank would be very intersting, the problem would be the decaying organic matter. That is, the constant worsening of water quality. In nature the system is large, our tanks are relatively small, even a large one.

I agree with @Bas Pels, you would need to find a leaf that was very slow to decay.

I actually have this sort of tank already, but I use live plants, rather than dead leaves, in a matrix of twiggy bits of wood, with some structural leaf litter.

It wasn't a deliberate decision to create this sort of habitat, but I found that fish did very well in my spare plant/wood/quarantine tank, where I just dumped any bits of dead wood that I'd picked up along with any spare moss, Java fern, Bolbitis, Anubias, Limnobium etc. Eventually I gave up any pretence of aquascaping the tanks (or tieing on the moss, ferns etc) and they now all look like this.

This is

Copella arnoldi

, after they had spawned in their quarantine "jenga" tank. The whole tank looks like this, there are only very limited spaces amongst the leaf/twig/plant matrix.



cheers Darrel

[Bas Pels]

The name jenga tank did set my mind working. I once had a large pile of driftwood in my 4 meter (13 feet) tank and I can only agree that it worked very nicely.

[bekateen]

While such a tank would be very intersting, the problem would be the decaying organic matter.

That is, the constant worsening of water quality. In nature the system is large, our tanks are relatively small, even a large one.

I agree with @Bas Pels, you would need to find a leaf that was very slow to decay.

Yes I agree good water quality would need to be maintained. And to reference previous posts about biotope tanks, almost always someone points out (correctly so) that the biotope can't easily be reproduced exactly in the aquarium setting. Therefore the goal would be, in my perspective, to create the essence or effect of the biotope while conceding to the limits of aquarium care.

Another thing, you'd lack the food source that makes these sites popular with the fish - the high abundance and variety of invertebrates feeding on the plant matter, which are then food for the fish. I suppose you could stock your tank with inverts... but which ones? Scuds? Ghost shrimp? Do you want chironomids hatching in your house? Then again, these too add to the bioload of the tank. So compromise will be needed.

I actually have this sort of tank already, but I use live plants, rather than dead leaves, in a matrix of twiggy bits of wood, with some structural leaf litter.

As Darrel did, I would think the effect would be created with wood sticks, branches, and live plants of mixed textures (stem, leafy, mossy, etc.). I'd add some dead leaves for tannins or for grazing upon, but not an excessive amount of dead material. Nuts? Maybe, but I wouldn't know which ones to add or why? Fruit? Probably not, unless you're feeding peppers, string beans, or zucchini to your plecos and this is your delivery mechanism.

The other element I'm considering about these is arrangement: I'm not envisioning merely packing the tank, as Darrel did (I too have a tank like that; it's great, but not what I'm thinking of). Rather, set up the tank so that there is a clear open space between the debris shelf ("kinon" as the authors called it) and the substrate. Since the kinons described in the paper were along shores, I envision the kinon formed like a shelf at the water surface and jutting out into the upper regions of the tank.

I've shared in a few places that I have several driftwood pieces that have floated in my tanks for years. I grow lots of Java moss, plus a few small Anubias and Java ferns on top of these. These are essentially kinons, but they are solid below water ‐ there's no web of spaces under these for fish to live and breed within.

Perhaps, if you have a Matten filter, you could poke multiple interweaving sticks into it near the water surface and then decorate the sticks with plants, dead leaves, etc., accordingly. Even position some light wood caves and tubes within for spawning sites. That's what I'd like to see someday, and try myself sometime too.

Cheers, Eric

[dw1305]

Hi all,

.....Another thing, you'd lack the food source that makes these sites popular with the fish - the high abundance and variety of invertebrates feeding on the plant matter, which are then food for the fish. I suppose you could stock your tank with inverts... but which ones? Scuds? Ghost shrimp?

Plenty of different snails (Physella, Ramshorn, MTS, River limpets - Acroloxus), Ostracods and Copepods and then Crangonyx and Asellus? I "picked my own" for the last two, but you can buy them for lab. use because they are water quality bioassay organisms.

The other element I'm considering about these is arrangement: I'm not envisioning merely packing the tank, as Darrel did (I too have a tank like that; it's great, but not what I'm thinking of). Rather, set up the tank so that there is a clear open space between the debris shelf ("kinon" as the authors called it) and the substrate. Since the kinons described in the paper were along shores, I envision the kinon formed like a shelf at the water surface and jutting out into the upper regions of the tank.

I've shared in a few places that I have several driftwood pieces that have floated in my tanks for years. I grow lots of Java moss, plus a few small Anubias and Java ferns on top of these. These are essentially kinons, but they are solid below water ‐ there's no web of spaces under these for fish to live and breed within.

Perhaps, if you have a Matten filter, you could poke multiple interweaving sticks into it near the water surface and then decorate the sticks with plants, dead leaves, etc., accordingly. Even position some light wood caves and tubes within for spawning sites. That's what I'd like to see someday, and try myself sometime too.

I think the matten filter idea is a potential runner, an even easier option might be to wedge bamboo canes between the front and back glass and then just sit the twigs, caves etc on top of them.

cheers Darrel