Acanthurus triostegus

Acanthurus triostegus (convict tang or convict surgeonfish) is a small surgeonfish in family Acanthuridae of the order Perciformes. It is typically about 10 cm (3.9 in) long, but some individuals may grow larger than 20 cm.[1]These tangs are widespread. They are found in the Indo-Pacific except for seas around the Arabian Peninsula, in the Pacific at the Hawaiian Islands, and in the Eastern Pacific they are found in the lower Gulf of California and down to Panama, including the Revillagigedo Islands, Clipperton Island, Cocos Islands, and Galápagos Islands with some reports throughout the Mediterranean and Adriatic Sea.