The marine angelfish and the butterfly fish can only be distinguished by the spine on each gill cover of the angelfish. Marine angelfish and the related butterfly fish number more than 150 in species. They live mostly in shallow seas and some estuaries in pairs or small groups. Both can usually be found around reefs, rocks or coral formations. In most of these fish even the young will bear the same brilliant colors, while in others the difference is so great that one might think they are not of the same species.
Angel fish tend to be solitary creatures that frequent the same territory day after day.
They are always near a shelter into which they can dart when disturbed. In an aquarium the adults will be aggressive towards each other but when there are no other angelfish in the aquarium they become tame and will even eat from your hand. The most beautiful of the angelfish is the rock beauty which is colored jet black in front with yellow on its hind quarters and fins that are yellow with red spots. This is an extremely curious fish that will draw near any under water swimmer. Since angelfish have small mouths armed with numerous tiny teeth they feed on small invertebrates which they can crush.