Coral groupers are piscivores because they primarily eat fish. Juvenile coral trouts eat crustaceans while adults eat a variety of reef fish, including juveniles of their own species. Yes, you read that right: adult coral trouts sometimes eat babies of their own kind!
They hunt in two different ways: by ambush and prowling. During ambush, they hide and remain very still before attacking passing prey. When prowling, they move slowly toward their target (such as schooling fish) and suddenly attack at a great speed.
Sea hares also change the type of food they eat throughout their life cycle. As larvae, they eat red algae, while as adults they can also forage on green and brown algae.