saltwater, reef fish
Pennant Coralfish
Heniochus acuminatus
Compressed disc-like body with a white ground color and two broad, diagonal black bands. The most striking feature is the extremely elongated white fourth dorsal spine, forming a long pennant. The soft dorsal fin, caudal fin, and pectoral fins are yellow.
- Habitat
- Found in both lagoon and seaward reefs at depths ranging…
- Size & weight
- Typically reaches a length of 15 to 20 cm (6 to 8 inches…
- Diet
- Omnivorous, feeding primarily on zooplankton in the wate…
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Physical characteristics
Compressed disc-like body with a white ground color and two broad, diagonal black bands. The most striking feature is the extremely elongated white fourth dorsal spine, forming a long pennant. The soft dorsal fin, caudal fin, and pectoral fins are yellow.
Habitat & distribution
Found in both lagoon and seaward reefs at depths ranging from 2 to 75 meters. Geographically distributed throughout the tropical Indo-West Pacific region.
Behavior
Often found in pairs or solitary, though adults may occasionally form small groups. They are diurnal, active during the daylight hours and seeking shelter in reef crevices at night.
Diet
Omnivorous, feeding primarily on zooplankton in the water column as well as benthic invertebrates and coral polyps.
Reproduction
Pelagic spawners. They release eggs into the open water where fertilization occurs. The larvae are planktonic and float with the currents before settling onto the reef.
Ecological role
Functions as a corallivore and planktivore. Juveniles occasionally act as cleaner fish, removing parasites from other fish species.
Similar species
Often confused with the Schooling Bannerfish (Heniochus diphreutes). The Pennant Coralfish has a more angular breast and a longer snout. The Moorish Idol (Zanclus cornutus) is also similar but has a tubular mouth and lacks the yellow dorsal fin of the bannerfish.
Identification tips
Look for the exceptionally long white dorsal filament and the two thick black bands. The yellow trailing edge of the dorsal and tail fins is a key identifier.
Interesting facts
Also known as the Longfin Bannerfish. Unlike their close relatives, the Schooling Bannerfish, adults of this species are more territorial and are less likely to be seen in massive schools.