I have some issues with petsmart fish, but that's my problem. Oto fish aren't the best swimmers, and you did just get the little guy, give him a little bit to find a hiding spot to call his own and he'll probably start going to town when you go to bed. They don't tend to be that active, and they are nocturnal by nature, if you only have one and you have a lot of algae he will sit in one spot and eat until it's all gone, slide down a little and eat some more. Depending on your stock I would suggest keeping a school of 7 or more for that sized tank, especially if you want to see them school.