Fish ID: Reef Bannerfish

Butterflyfish reef bannerfish nsw foa
Family Butterflyfish (CHAETODONTIDAE)
species Heniochus acuminatus
size to 20cm
locality Along reef walls
behaviour Usually singular, occasionally in pairs
range Indian and Pacific Oceans

Bannerfish are easily recognisable by the banner-like dorsal fin (hence sometimes called the Longfin) which makes them look a little like a Moorish Idol, though they are in the Butterflyfish family.