Steephead Parrotfish

Chlorurus microrhinos usually grows to be about 80 centimetres (31 in) long. These parrotfish are greenish blue, with a brilliant blue band behind the corner of the mouth and a wide blue patch along the head. Rarely, some individuals may be uniformly yellowish-tan. The cheek is crossed by an irregular line, below which the colour is usually greenish-yellow. Larger fishes are uniformly dark, greenish brown, turning greenish blue only with age, but they do not undergo as radical a colour change with growth as do other scarids. They have nine dorsal spines, 10 dorsal soft rays, 3 anal spines, and 9 anal soft rays. The tail is crescent-shaped in large terminal males, while in juveniles it is rounded. Adults show large exposed blue-green tooth plates, with one or two canines on each side of the upper plate. Large males develop a prominent forehead (hence the common name of blunt-head parrotfishes). Juveniles are black with some horizontal white stripes. Some geographic variation exists between Red Sea, Western Indian Ocean, and Pacific populations, and an unusual reddish-tan phase occurs in the central Pacific.

This species is one of the most widespread. It is present in the extreme east Indian Ocean and the Pacific Ocean, from the Ryukyu and Ogasawara Islands to Indonesia and the Australian Great Barrier Reef, Lord Howe Island, New Caledonia, and French Polynesia, and eastwards to Oceania (Hawaii and Easter Island excluded).