Acanthurus coeruleus is a tropical surgeonfish who prefer a water temperature of around 26ºC. It has a continuous dorsal fin with 26 to 28 rays and 9 spines and a long anal fin with 24-26 rays and 3 spines.

Acanthurus coeruleus may be up to about 40 cm in length.

Blue and at night aubergine-colored but always with with bright blue eyes and mouth and bright blue lines on the fins. The juveniles are bright yellow with blue edges to the fins and eyes and mouth.

In coastal waters on rocks and coral reefs to about 40 meters deep. Often the shallow water between the algae observed. Its diet consists of aquatic plants and sediment.

Western Atlantic from New York to Brazil.