I really never had them personally, but what I heard is that they rip and nip open corals and anemone's to feed on the un-digested food. But again, I'm not an expert I just did some research for you :joy: , I never had them personally. But thats what they are known for. Who knows there could be some rarities where it wont damage any coral or anemone. You really can't tell. Not all of them are the same in agressiveness.