About Acanthurus blochii Valenciennes, 1835
Acanthurus blochii Valenciennes, 1835 has 9 spines and 25 to 27 soft rays that support its dorsal fin, while the anal fin is supported by 3 spines and 24 or 25 soft rays. It has a relatively large spine on the caudal peduncle, and the spine’s length measures between one third and one 4.4th of the head length. The species’ overall body color is blue-grey, with a yellow spot behind the eye and a white bar on the base of the caudal fin. A dark blotch surrounds the spine on the caudal peduncle, and the caudal, dorsal, and anal fins are dark blue to black. When observed underwater, the overall body color appears black, interrupted by a lighter band across the caudal peduncle. This species reaches a maximum standard length of 45 cm (18 in).
Acanthurus blochii has a broad distribution across the Indo-Pacific, ranging from East Africa between Djibouti and South Africa east to Hawaii, south to northern Australia and Lord Howe Island, and north to the Ryukyu Islands of southern Japan. It inhabits the outer slopes and lagoon slopes of coral reefs, where it grazes on algae and detritus, particularly from compacted sand.
