I've got one in my tank at home. It's probably my favorite fish. I'm a huge fan of any Halichoeres wrasse in a reef. Probably nipping at small inverts around your acan, not the coral itself. All of them I've had experience with roam the entire tank. Never had a problem with coral predators or nuisance organisms with one of these in a tank, even when learning later a coral or two came from questionable sources.