Pinstriped Angelfish

Genicanthus watanabei, like the other angelfishes in the genus Genicanthus, shows sexual dichromatism, the males and females show differences in colour and pattern. The males are pale blue to bluish-grey on the upper third of their bodies with the lower two thirds having 8 horizontal, thin black stripes, the highest of these end in a patch of yellow colour. The females are overall light blue colour with wide black bars across their head and a black spot on the snout. In both males and females there is a wide submarginal band on the dorsal and anal fins, and on the lobes of the caudal fin. Juveniles somewhat resemble females in colour. In both sexes the forked tail narrows at its base to create a "swallow tail". The dorsal fin contains 15-16 spines and 15-16 soft rays while the anal fin has 3 spines and 14-17 soft rays. This species attains a maximum total length of 15 centimetres (5.9 in).

Genicanthus watanabei is found in the Pacific Ocean. It ranges from Taiwan east to the Cook Islands and Tuamotu Archipelago, north to the Ryukyu Islands and south to New Caledonia and the Austral Islands. It also occurs on the Great Barrier Reef with juveniles reaching as far south as Sydney.