About Halichoeres prosopeion (Bleeker, 1853)
Halichoeres prosopeion, commonly called the twotone wrasse or half-grey wrasse, is a small fish that reaches a maximum length of 13 centimeters. It has a thin, elongated body with a terminal mouth. Its body coloration varies slightly based on age and geographic distribution. For juvenile wrasses found in Australia and eastern Papua New Guinea, the body is white with four black stripes that run from the snout all the way to the tip of the caudal fin. In the rest of the species' distribution range, juveniles also have a white body with four black stripes, but these stripes do not reach the tip of the tail; in these juveniles, the caudal fin and caudal peduncle are yellow. For adults of both sexes and across all distribution areas, body coloration is fairly consistent: the anterior portion of the body is grey-blue, and the posterior portion is yellowish, with a slight gradient at the junction between the two color zones. A dark spot is present on the first rays of the dorsal fin. The half-grey wrasse is widespread across tropical and subtropical waters of the western Pacific Ocean, ranging from Indonesia to the Philippines, and also occurring in French New-Caledonia and southern Japan. This wrasse lives on outer reef slopes and in lagoons within coral-rich reef areas, and can be found from the surface down to a depth of 40 meters.
