I have a pixy hawk (Cirrhitichthys oxycephalus) in my 65g, he doesn't bother the corals at all. He perches all over the place, but never directly on a coral, and seldom bothers with the crabs or snails. He did kill a cleaner shrimp after a few months though. Hawks are fun and if you don't mind the possiblity of losing a few inverts now and then they're safe, just watch out for their feisty little personalities - I wouldn't house any shy or delicate fishes with one of these guys.