they may, they may not. my puffs left the gobies alone for quite some time, until they decided to try to spawn.......... scarface became scartail (had a big chunk missing out it....). nothing serious, the bbgs can hold their own, but cories are pretty peaceful, and can be active in groups. youre better getting fish that won't attract so much attention to themselves, like bbgs or otos or a plec of some kind.