Just when you thought it couldn't get any stranger-Another concept aquarium to try.

You are probably either fed up with our obsession about leaf litter biotopes, or equally as geeked-out as we are about 'em, right?

Yeah, kinda figured! 

We make it a point to scour scientific papers and scholarly research articles for topics relevant to our obsession. The other day, I stumbled on a cool paper about...floating leaf litter banks!

(Photo from Carvalho, et al.)

Yeah, right? Cool!

So imagine, if you will, a "classic" submerged leaf litter bed in Amazonia, composed of a variety of leaves, branches, twigs, seed pods, and other botanical materials...yet floating on the surface of the water surface! What you get is a fairly deep layer of plant materials colonized by fishes and other creatures, which forage on the macro invertebrate life found in these assemblages. Biologists call this an "ephemeral" habitat, as it is transitory or temporary as it slowly breaks apart. 

Okay, so it slowly breaks apart over months and months...

Nonetheless, I found this an irresistibly interesting niche! Reminds me of the Sargassum "forests" of the Caribbean and Tropical West Atlantic!

According to one study, these floating or partially submerged leaf litter banks either accumulate among the branches of riverside vegetation during the high water season, gradually floating downstream, or stay anchored in place by fallen tree trunks and other large materials, ultimately forming a more "traditional" submerged leaf litter bed.

It was discovered that many fish species associate with these floating litter banks for the entire wet season, and one of the reasons they stay put is because their food sources are there, too! In fact, a species of "water bug", Weberiella rhomboides, is found almost exclusively in these floating banks, attracting large numbers of insectivorous fishes, like characins, catfishes, knife fishes, and others. 

In other words, these stands of floating leaves and botanicals are literally a "moveable feast", a veritable "floating fish buffet", if you will! The fish populations found in these environments are typical of what you'd expect to find in a more "static" leaf litter environment.

What fishes would you expect to find in this cool niche? Well, it's kind of a "who's who" of blackwater, leaf litter zone dwellers, some of which are very familiar to us as hobbyists- for example, characins like Hemmigramus species, Moenkhausia species, the killifish Rivulus ornatus, and of course, cichlids, including a number of ApistogrammaCrenicichla, Hypselecara, and the much-loved Mesonauta festivus, to name a few. 

And then there is that most ubiquitous of leaf-litter-dwelling characins...one which I've never seen in the hobby, but I see everywhere in leaf litter population studies, Elachocharax pulcher! I've been told that it shows up occasionally, but being a leaf litter dweller, it probably evades capture by local fishers, and it's cryptic coloration makes it less than exciting for any but the most geeked-out aquarists like me and you!

The next question is, could you recreate a facsimile of this environment in an aquarium? Would you want to?

The answer is, "Of course!"

Now, I admit I haven't tried this yet, but being ever the enabler, I want to encourage someone with an extra tank and a healthy fascination with this type of niche to try it! 

Just how would you do this? Well, I envision it being pretty straightforward. You could use most of the same aquatic botanicals that we utilize in our "New Botanical"-style aquariums, but you'd go easy on the boiling. In other words, you'd give your botanicals thorough cleaning, as is consistent with our responsible practices regarding the addition of items to our aquarium.

You'd boil and/or steep the materials, too. However, you probably would not obsess over boiling things like "Savu Pods" , "Jungle Pods", etc to the point where they sink (sounds dreamy already, huh?), as this would kind of defeat the purpose, right? And I'm thinking like small pieces of Spider Wood or even Manzanita, which are maddeningly buoyant when we want them to sink, right?

Ohh, this is getting good...

I'd imagine that you'd want a shallow, wide aquarium, and probably would filter it with an outside power filter or canister filter with the return positioned in such a way as to minimally disturb the surface. You'd essentially be creating a diverse assemblage of botanicals, just like you would if you were doing a "conventional" leaf-litter display (I love that- a "conventional leaf litter display"- look how far we've come...). 

Now, eventually, some of this stuff would sink, or be trapped below the floating "matrix", and you'd end up with materials on the bottom...okay...cool!  It would transition naturally to a more "conventional" botanicals-on-the-bottom display. So this is essentially an "ephemeral display"- transitioning from a "floating leaf litter bed" to a submerged leaf litter aquarium! How cool is that? Of course, you could probably keep it going by replacing the leaves and such as you would anyways, right? And as the wood becomes submerged, you'd "let it do it's thing", and/or replace/add new pieces.

I would wager that NO ONE has ever really tried this in an aquarium before- at least, not intentionally. If you have, I would love to see it! If you haven't, I'd love to see you DO it! Hell, now I'm convincing MYSELF to do it! I see a build video coming up...I'm on the phone with Johnny Ciotti and Luis Navarro today about this, lol. I would assume that there might be some challenges and considerations for running a tank like this, but it's worth a try, IMHO.

Okay, I suppose I should curb my enthusiasm a bit, but still, imagine the possibilities with a tank like this?

No, I won't curb my enthusiasm, on second thought. I'll start scheming!

Who's in?

Stay excited...Stay geeked-out...

And Stay Wet.

Scott Fellman

Tannin Aquatics

Oh...and has ANYONE seen that darned Elachocharax pulcher?


CARVALHO, Lucélia Nobre et al. Second floor, please: the fish fauna of floating litter banks in Amazonian streams and rivers. Neotrop. ichthyol. [online]. 2013, vol.11, n.1 [cited  2016-06-27], pp.85-94. Available from: <http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252013000100085&lng=en&nrm=iso>. ISSN 1679-6225.  http://dx.doi.org/10.1590/S1679-62252013000100010.



Scott Fellman
Scott Fellman


Leave a comment