Chaetodontoplus duboulayi has an largely blue body marked with darker wavy lines. The snout is yellow as are the pectoral, pelvic and caudal fins. There is a yellow stripe which extends along the base of the dorsal fin and a wide vertical, yellow bar to the rear of the eye and the operculum is white. They are sexually dimorphic with the males being marked with sinuous blue lines along their flanks while the females have yellow or blue spots. The dorsal fin contains 11 spines and 22 soft rays while the anal fin contains 3 spines and 21 soft rays. This species attains a maximum total length of 28 centimetres (11 in). Chaetodontoplus duboulayi Is found in the southwestern Pacific Ocean where it occurs along the northern Australian coast from Shark Bay in Western Australia to Moreton Bay in Queensland and as far south as Lord Howe Island in the Tasman Sea. It can also be found in the Aru Islands of Indonesia and along the southern coast of New Guinea. There have also been reports from Taiwan.
