I keep a trio of yo yo loaches in a tank with a small rainbow shark, parrot cichlids, and a convict cichlid. My loaches pretty much ignore any other fish and just do their own thing. They are very active and playful with each other, and they add a lot of character to my tank. Like LWB said, if you get at least a trio, you shouldn't have any problems, and they are a fun fish to keep.