You might want to find out from LFS or who ever you bought these lovely otos from just to make sure you can feed them.
A lot of times, unfortunately, LFS sells these oto from the wild and these are very hard to feed if you do not have natural green algae for them to feed on.
Tank bred are the best as these would usually be fed with algae wafers and vegetables.
BTW, otos, they are pretty active and are a social specie meaning a minimum group of at least 6 would be better but that is pretty close to fully stocking your 10 gal imho, you might be able to add a betta if temperment wise is ok, but thinking woud need to be pretty densely planted as well.