They are reef safe in a sense that they will not feed on corals....other invertebrates. However, they're more than happy to eat all of your crustaceans (except cleaner shrimps). Mine does not bother any of my inverts, even a 1" emerald crab. They're kind of a pain in the neck in a reef tank because they tend to knock off things when trying to move around. Otherwise, a great fish to have!