An oto will probably stay healthy and happy in a mature, well planted tank. They need a vegatable diet that will probably demand more of a keeper than dropping in flakes or pellets. I'm feeding mine cucumber right now, but the best is probably algae you would grow yourself.
There are stories of perfectly healthy otos dropping off for unknown reasons . . . but I think it's probably stress-related from people buying them soley as "algae eaters" and then not providing them with proper tank furnishings and food.
Delicate fish, they need a mature tank, lots of plants and algae. Also need to be in groups or more, otherwise they can get lonely, finally they must be with other fish which are not going to harm them, or do anything like that.
I do not own some oto's, but i really want to when my tank is ready for them.
