At a glance

Length

Up to about 25 cm

Depth

Reef slopes and lagoons, 2–75 m

Diet

Plankton from the water column, and small invertebrates picked off the reef

Status

Least Concern

How to recognise it

Two broad black bands across a white body, yellow tail and rear fins, and a long white pennant trailing from the dorsal fin like a flag from a pole. Usually in pairs.

Where we meet them

On almost every reef we dive — hanging under overhangs and along the drop-offs, and often the first to come and look at you on the safety stop.

Best timeYear-round.

Behaviour

Adults pair up and keep to a patch of reef; juveniles sometimes clean parasites off bigger fish. They feed in open water on plankton and swoop down for small invertebrates on the reef.

Diving with them

Hold still and they come to inspect you. Easy to photograph, easy to spook with a fin kick — keep your buoyancy and they stay.

Status & protection

Least Concern. Common across the Indian and Pacific oceans; collected for aquariums in places, but not threatened.