If you can get some Repashy gel food they are much easier to keep well fed. That's the biggest problem with Otos, they come into the stores in bad shape and usually starve before you can get them back into good shape.
These are some PetSmart $1.00 Otos I picked up back around the first of the year. After a couple months of pampering and feeding Repashy gel they spawned...
Very cool little fish once you master keeping them. They are a tiny bio-load and work very well in small tanks.
Dennis