” Parrotfishes are a group of about 95 species traditionally regarded as a family (Scaridae), but now often considered a subfamily (Scarinae) of the wrasses. They are found in relatively shallow tropical and subtropical oceans throughout the world, displaying their largest species richness in the Indo-Pacific. They are found in coral reefs, rocky coasts, and seagrass beds, and play a significant role in bioerosion.
Parrotfish are named for their dentition, which is distinct from other fishes, including other labrids. Their numerous teeth are arranged in a tightly packed mosaic on the external surface of their jaw bones, forming a parrot-like beak with which they rasp algae from coral and other rocky substrates (which contributes to the process of bioerosion).
Maximum sizes vary within the family, with the majority of species reaching 30–50 cm (12–20 in) in length. However, a few species reach lengths in excess of 1 m (3 ft 3 in), and the green humphead parrotfish can reach up to 1.3 m (4 ft 3 in). The smallest species is the blue lip parrotfish (Cryptotomus roseus), which only reaches 13 cm (5.1 in).” https://en.wikipedia.org/wiki/Parrotfish