Pencil Urchin
Pencil Urchin
As long as the fish that you keep are piscivorous; i.e. lionfish, some groupers, frogfish, etc.... Most triggerfish, puffers, porcupinefish are all hard shell animal eaters. Moray eels are risky but it depends on the species. I know that Chainlink and Snowflake morays eat crustaceans. The morays with the longer non-serrated teeth generally eat fish and cephalopods.
James