Black Pyramid Butterflyfish

Like most other butterflyfish species, Hemitaurichthys zoster is a small fish, with a maximum length of 18 cm (7.1 in). Its body is compressed laterally with a rounded profile, but the snout is somewhat stretched, with a small terminal protractile mouth. The body is black, crossed in its center by a broad white trapezoid band with a yellow top, corresponding to the center of the dorsal fin. The caudal fin is white.

Hemitaurichthys zoster is widespread throughout tropical and subtropical waters of the Indian Ocean, from the eastern coast of Africa to India and Java, Indonesia. It lives in large schools on outer reef slopes, from which it can sally into open water to feed on plankton. The depth range at which this species is typically found is 3–40 m (9.8–131.2 ft).

Hemitaurichthys zoster was first formally described as Chaetodon zoster in 1831 by the English zoologist Edward Turner Bennett (1797–1837) with the type locality given as Mauritius. The specific name zoster means "belt" or "girdle" and is presumed to refer to the wide, white band in the middle of this fish's body.