Heniochus acuminatus
Encounter Rate
Spotting Difficulty
Best Season
Year-round
Depth Range
2-40 meters
The longfin bannerfish is one of the most elegant and recognisable butterflyfish on Komodo's reefs, distinguished by its bold black and white banding and an enormously elongated white dorsal fin filament that trails behind the fish like a streaming pennant. Reaching about 25 centimetres in body length, this graceful species is sometimes called the poor man's Moorish idol due to its superficial resemblance to that iconic reef fish. In Komodo, longfin bannerfish are commonly found in pairs or small groups along reef walls, drop-offs, and around coral outcrops at moderate depths. They are planktivores that hover in mid-water picking zooplankton from the current, and their paired swimming behaviour — two individuals often mirror each other's movements in perfect synchrony — is a charming sight on any dive. Unlike many butterflyfish that are shy and difficult to approach, longfin bannerfish are relatively tolerant of divers and will often continue feeding as observers settle nearby. Their striking monochrome pattern with the flowing dorsal filament makes them one of the most photogenic reef fish for both beginners and experienced underwater photographers.
Average Size
15-20cm
Size Range
8-25cm
Maximum Size
25cm
Planktivore that hovers in mid-water feeding on zooplankton. Also picks small invertebrates and algae from the reef surface.
The longfin bannerfish is one of the most elegant and recognisable butterflyfish on Komodo's reefs, distinguished by its bold black and white banding and an enormously elongated white dorsal fin filament that trails behind the fish like a streaming pennant. Reaching about 25 centimetres in body length, this graceful species is sometimes called the poor man's Moorish idol due to its superficial resemblance to that iconic reef fish. In Komodo, longfin bannerfish are commonly found in pairs or small groups along reef walls, drop-offs, and around coral outcrops at moderate depths. They are planktivores that hover in mid-water picking zooplankton from the current, and their paired swimming behaviour — two individuals often mirror each other's movements in perfect synchrony — is a charming sight on any dive. Unlike many butterflyfish that are shy and difficult to approach, longfin bannerfish are relatively tolerant of divers and will often continue feeding as observers settle nearby. Their striking monochrome pattern with the flowing dorsal filament makes them one of the most photogenic reef fish for both beginners and experienced underwater photographers.
This species plays an important role in the marine ecosystem of Komodo National Park. Responsible diving practices help protect these animals and their habitat for future generations.
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No — they are often confused but belong to different families. Longfin bannerfish (family Chaetodontidae) have a white dorsal filament, while Moorish idols (family Zanclidae) have a yellow tail and more complex colour pattern. Both are beautiful reef fish found in Komodo.
