Acanthuridae

Palette surgeonfish

Paracanthurus hepatus

When alarm strikes whole groups squeeze between cauliflower coral branches

• Black
• Blue
• Yellow
• Tropical
• Regional distribution
• Marine fish
• Compressed
• Compressed cross-section
• Medium
• Tropical fish

Dressed in an arresting livery resembling an artist's palette, the palette surgeonfish is one of the most beloved and visually striking acanthurids inhabiting Indo-Pacific coral communities. Its royal-blue oval torso is set off by a dramatic black ribbon that arcs over the back from the eye, sweeping around the flanks in a circular loop that frames a bright blue oval, while the caudal fin displays a contrasting bright yellow wedge bordered in bold black. A sharp defensive spine rests recessed within a groove along the yellow caudal peduncle. Distributed from the coast of East Africa across Southeast Asia and the Great Barrier Reef to Samoa and the Line Islands, it thrives on clear, current-swept seaward reef crests and outer slopes between two and forty meters depth. Groups associate intimately with branching cauliflower corals (Pocillopora eydouxi), hovering above the stony branches to feed on drifting plankton and benthic algae. When alarmed, entire aggregations dive instantly into the narrow gaps between coral fingers, wedging securely to frustrate predators. Maximum total length reaches thirty-one centimetres.

Sources: Australian Museum — Palette Surgeonfish, Paracanthurus hepatus