Parrotfish, bite off chunks of coral to get at the algae inside or outside.
Triggerfish,bite chunks of coral to get at the invertebrates hiding inside.
The habits of some territorial damselfish are destructive to the corals they claim as their property. The Caribbean threespot Damselfish bites the coral, causing an open wound so that algae can take a hold, and in this way cultivates algal mats on both staghorn and common star coral. However this algae meal also attracts grazing parrotfish which muscle in and gnaw the coral to get a good bite of algae inside and out.