two kind of catfish

Last week I moved my one otocinclus into the window tank. I can't make up my mind what to do with this lonely fish. It was starting to look skinny in the main tank, and rather listless- instead of constant busy nibbling it would lie still for long periods, then make frantic-looking darts around the tank- to this spot, then another, then another- without feeding long in any one area. I really think it was running out of algae to eat in there. Between the trumpet snails, nerites, limpets and shrimps- not enough left for the oto maybe.

So I took a chance and moved it over here where there are still some diatoms, green spot algae and fungus growing out of driftwood. Even though plenty of trumpet snails in here too, and far more visible limpets, it seems like the oto is finding more food now. I did a slow acclimation but for the first day it looked pale and was breathing hard. Now its tummy is rounded again, and it moves about busy nibbling on surfaces again. It's cleaned all the diatoms off, but appears to be finding enough on wood and plants for the time being.

It is kind of cute, and also rather sad, that it hangs out with my cories at the substrate level sometimes. I wonder if it finds their company a bit companionable.

I am kind of hoping it will learn to eat algae wafers and zucchini from the cories, then maybe I can move it back into the main tank and supplement its diet that way. Soon it will be too cold in this tank.

Incidentally, when I was taking closeups of the oto among cories, I noticed this one catfish seems to have a bent tail- on the right

Before I thought well, maybe it just lets its tail drift up when resting. But when I look at the others- you can see it even though the photo is a bit blurry- their tails remain straight whether scavenging or at rest.

I hope it is just a birth defect and not an early sign of fish tuberculosis.