Angelfish

Genicanthus semicinctus like the other angelfishes in the genus Genicanthus, shows sexual dichromatism, the males and females show differences in colour and pattern. The males are marked with thin close-set wavy black, vertical bars which run from the back to two-thirds down the flanks with the lower third of the body being yellowish-orange. They have a yellow dorsal fin and yellow lobes with long filaments on the caudal fin which has black spots. The chest also has black spots. The females are plain dark grey on the back with a whitish abdomen and have dark lobes to the caudal fin. Their fins have thin blue margins and there is a black blotch above the eye, this has a vivid blue margin. The dorsal fin contains 15 spines and 15-16 soft rays while the anal fin has 3 spines and 17 soft rays. This species attains a maximum total length of 21 centimetres (8.3 in).

Genicanthus semicinctus is found in the southwestern Pacific Ocean. Here it is found only around Lord Howe Island, an Australian territory in the Tasman Sea, and the New Zealand outlying islands of the Kermadec Islands.