how the oto is doing

I am not sure. It seems to sit listlessly breathing hard sometimes (I can't figure out why- none of the other fishes look distressed) and other times dashes around the tank as if frantic, from spot to spot can't sit still. Yet it looks plump and the fins are usually perky.

I thought it would feed off the micro organisms on leaf litter, but I can't tell if it does. Or cleaned it off quickly and needs more?

It usually comes to substrate when the cories are feeding, now. Even when it is food I don't think appropriate for an oto. Today it was moving around as if feeding when I gave the cories betta flake, and the other day did this with hikari loach wafers. I hope it's not going to get sick from eating the wrong kind of food. If it's actually eating it.