Genicanthus melanospilos shows sexual dichromatism, the males and females have differing colouration.

The males have a background colour of bluish white on the body with many reddish black vertical stripes.

It is found throughout the Malay Archipelago into the southwestern Pacific Ocean as Far East as Fiji, north as far as the Ryukyu Islands south to Australia.

[1] In Australian waters it is found in the Indian Ocean of the Cocos (Keeling) Islands and Christmas Island, as well as the Ashmore Reef in the Timor Sea and the Great Barrier Reef off the coast of Cairns in Queensland .

[1] It occurs in areas rich in coral on the outer slopes of reefs and drop-offs.