Chaetodontidae

Longfin bannerfish

Heniochus acuminatus

Young fish run a cleaning service for parasite burdened neighbors

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

An exaggerated, pennant-like dorsal filament gives the longfin bannerfish one of the most theatrical silhouettes patrolling Indo-Pacific coral ramparts. Its disc-like, highly compressed white torso is divided by two broad, oblique jet-black bands: the first descending from the nape behind the head, and the second crossing the belly up towards the posterior dorsal margin. The brilliant yellow soft dorsal and caudal fins glow under tropical sunlight, while the prolonged fourth dorsal spine extends into a graceful, trailing white streamer that arches far past the caudal fin. Distributed across the tropical Indo-Pacific from the Red Sea and East Africa to the Great Barrier Reef and Society Islands, it frequents sheltered lagoons, channel passes, and steep seaward slopes between two and seventy-five meters depth. Pairs or loose aggregations hover serenely in the water column, picking pelagic zooplankton from passing currents and occasionally plucking parasites from larger reef clients. Maximum recorded total length attains twenty-five centimetres.

Sources: Australian Museum — Longfin Bannerfish, Heniochus acuminatus