Heniochus diphreutes Jordan, 1903

Species Nomenclature and Size

The schooling bannerfish (Heniochus diphreutes Jordan, 1903) is a small fish that reaches a maximum length of 18–21 cm.

Body and Dorsal Fin Structure

Its body is laterally compressed, and the first rays of its dorsal fin extend into a long white filament.

Body Coloration

The fish’s base body color is white, marked with two large black diagonal bands. Past the second black stripe, the dorsal, caudal, and pectoral fins are yellow.

Head and Mouth Features

The head is white, with black eyes connected by a black to gray band. Its short snout, which has black to gray spotting, holds a small terminal, extensible mouth.

Geographic Distribution

The schooling bannerfish is widespread across tropical, subtropical, and temperate waters of the Indo-Pacific. Its range extends from the eastern coast of Africa (including the Red Sea) to Polynesia and Hawaii, and from the Great Barrier Reef and southern Japan to the Kermadec Islands of New Zealand.

Preferred Habitat

It favors external reef slopes and channels.

Depth Range

It has a broad depth range, and is most commonly found at depths of 5–30 m, though it can occur as deep as 210 m in some locations.

Grouping Behavior

As its common name suggests, the schooling bannerfish lives in large groups.

Diet

It feeds on zooplankton in open water.

Cleaning Behavior

Juveniles may act as cleaner fish, and this cleaning behavior has also been observed in adults.

Breeding

This oviparous species forms pairs for breeding.

Observed Cleaning Interaction

Individuals have been observed cleaning parasites off the short sunfish (Mola ramsayi) off the coast of the Maldives.