Genicanthus bellus

Genicanthus bellus Is sexually dichromatic, the males and females show different colouration and patterning. The females, and the juveniles, have greyish to bluish background colouration and are marked with wide black bands and a blue longitudinal stripe on the lower flanks. The males' background colour is pale bluish to greyish and they have horizontal golden stripes along the centre of the flanks and another along the lower back. Also in the males the bases of the pectoral and dorsal fins are the same colour as the stripes on the body. The caudal fin are unpigmented frequently marked with patches of orange, these have filamentous extensions and are bright blue. The lips are also bright blue. In the females and juveniles there is a black stripe which runs vertically from the nape through and engulfing the eye but does not extend past the lower part of the orbit. A second black stripe begins immediately to the rear of the first, creating a right angle at the origin of the dorsal fin and the continuing along that fins base. Another black stripe commences at the right angle of the second stripe and runs diagonally downward to the lower lobe of the caudal fin. The last black stripe runs along the upper margin of the upper lobe of the dorsal fin, starting at the caudal peduncle. Each of these four stripes has margins of white or very pale blue. …

Genicanthus bellus has a wide but localised distribution in the western Pacific Ocean and eastern Indian Ocean. In the Pacific it has been recorded from Tahiti, Guam, Palau, Tonga, the Cook Islands, the Marshall Islands, the Philippines, southern Japan and southern Indonesia. Its preference for quite deep water may mean that this species is under-recorded. In Australian waters, it is found in the Indian Ocean of the Cocos (Keeling) Islands and Christmas Island, as well as Holmes Reef in the Coral Sea.