I'm looking to get a small bottom feeder for my 10 gallon. Are there any catfish that will stay small and don't require a school to act "normal"?
While otos are great fish, they really aren't "bottom feeders" so if the idea is you are looking for something to eat uneaten food and so forth off the surface of the substrate, otos are not going to accomplish that goal. In a 10 gallon you could put 3-4 normal corys or 6+ dwarf corys, as long as the water column isn't already overstocked with fish.
A few other options if you are explicitly looking for bottom feeders:
- a handful (or two!) of ghost shrimp
- some combination of snails
As long as you have fish that are small enough where they don't see the ghost shrimp as food, then having a half dozen or more ghost shrimp will keep your substrate nearly spotlessly clean. (And since most pet stores sell them as feeders, you can usually pick them up at a price of around 6 for $1). A decent-sized apple snail or two, or some nice ramshorns, would do a fine job keeping the substrate clear of uneaten food and also help with some algae control as well, while at the same time adding some real color to your tank. If you have live plants you need to be sure you choose plant-safe snails such as the European ramshorn (
Planorbis corneus or
Planorbis rubrum) and Malaysian Trumpet Snails (MTS); if you have all plastic plants then basically anything is open to you, including voracious plant eaters like the Columbian Ramshorn snail (
Marisa cornuarietis). As for Apple snails, I believer there are at least 4 different species that go by that name, and some are plant eaters while others are plant safe, so you really need to do your homework on those if you have a planted tank.