The schooling bannerfish (Heniochus diphreutes), also known as the false moorish idol, is a marine ray-finned fish, a butterflyfish from the family Chaetodontidae.

[2][3] Its body is compressed laterally, and the first rays of its dorsal fin stretch in a long white filament.

The short snout, spotted with black to gray, has a small terminal, extensible mouth.

The schooling bannerfish is widespread throughout the tropical, subtropical and temperate waters of the Indo-Pacific from the eastern coast of Africa, Red Sea included, to Polynesia and Hawaii and from the Great barrier reef, to south Japan to the Kermadec Islands (New Zealand).

[7] In some geographic areas, the schooling bannerfish is harvested for the aquarium trade and is commonly sold as a cheaper alternative to the Moorish idol.