About Heniochus acuminatus (Linnaeus, 1758)
The pennant coralfish (Heniochus acuminatus) is a small-sized fish that reaches a maximum length of 25 cm, while the average size most commonly observed in the wild is around 15 cm. Its body is laterally compressed, and the first rays of its dorsal fin extend into a long white filament. The base body color is white, marked with two large black diagonal bands. Past the second black stripe, the dorsal and caudal fins are yellow, and the pectoral fins are also yellow. The head is white, the eyes are black and connected to each other by a black band. The snout, which has black spots, is slightly elongated, and has a small terminal protrusible mouth that can be extended. Juvenile pennant coralfish do not yet have the white area past the second black stripe that adult fish have. The pennant coralfish is easily confused with the similar-looking schooling bannerfish (Heniochus diphreutes, also called reef bannerfish). The main visible differences between the two are: the pennant coralfish (reef bannerfish) has a longer snout with darker snout spots, and its pelvic fin is longer with a rounded end, while the schooling bannerfish has a smaller pelvic fin with a more angular end. The pennant coralfish is widespread across tropical and subtropical waters of the Indo-Pacific, ranging from the eastern coast of Africa (including the Red Sea) to Polynesia, and from southern Japan to the southern Great Barrier Reef. This species prefers relatively deep water from 15 to 75 m (49 to 246 ft) deep, found in protected lagoons, channels, and outer reef slopes.
