Appearance
Pomacanthus xanthometopon grows to a maximum length of 38 centimetres (15 in) and is laterally compressed. The mouth is just above the tip of the snout. The fins are large and rounded and are yellow, some edged with blue round the margins. The dorsal fin is set just in front of the caudal region, has a distinctive black eyespot at the base and has 13–14 spines and 16–18 soft rays. The anal fin has 3 spines and 16–18 soft rays. The scales are pale blue edged with yellow giving a reticulated pattern. The face is yellow with a dense network of brilliant blue lines on the bottom half and a plain yellow mask around the eyes. Juveniles are quite differently coloured with 6 vertical white bars separated by pale blue lines and a caudal fin barred in 2 shades of blue. The juveniles change colour gradually after reaching a length of 7 to 12 centimetres (2.8 to 4.7 in).

