Parrotfish

Parrotfishes are a group of marine fishes that live in shallow tropical and subtropical oceans around the world. Previously considered to form the large family of wrasses, these fish are now thought to belong to their own family. 
Their numbers are largest in the Indo-Pacific region where they are found in and around coral reefs and seagrass beds. They play an important part in bioerosion. There are about 95 species of parrotfish living today. Parrotfish are very colorful. Their name comes from the parrot-like beak formed by their teeth. The buccal cavity (cheek) of the parrotfish secretes the 'sleeping sack' that the fish sleeps in overnight. It is a semi-translucent sack which completely surrounds the parrot fish. In the morning the sack is discarded. During the day you will see them on the seabed floor.