About Heniochus pleurotaenia Ahl, 1923
The phantom bannerfish (Heniochus pleurotaenia Ahl, 1923) is a small fish that reaches a maximum length of 17 cm. Its body is laterally compressed, and the first rays of its dorsal fin extend into short, white, feather-like filaments. Its base body color is white, with light chocolate to dark colored markings, including a brown face mask that covers the mouth and eyes, and extends to the base of the first dorsal fin rays. It has an elongated snout with a small, terminal, protractile mouth. A small horn sits between the eyes, and a rounded frontal growth creates a concave profile to the fish's face. A second dark marking forms an inverted "v" shape that starts at the ventral fins and ends at the anal fin. A third chocolate-colored marking runs from the last dorsal fin rays to the base of the caudal peduncle. This species can be confused with the very similar horned bannerfish, Heniochus varius, which lacks the inverted v pattern on the sides. Juveniles, which do not have the white insert, can be told apart by the shorter extension of the first dorsal fin rays. The phantom bannerfish is widespread across tropical and subtropical waters of the central Indo-Pacific, ranging from the Maldives to the western coast of Thailand, and from the southern tip of India to Java, Indonesia. It lives in coral-rich areas in shallow lagoons and external reef slopes, from the surface down to 25 meters depth. It occurs in pairs or aggregations: in Indonesia, it is typically found in pairs in coastal waters, while it may gather into schools in offshore areas, and can form very large schools in some locations such as the Maldives. It can be found at a range of depths, and is frequent on shallow reef crests exposed to surge. It appears to prefer mixed algae and coral habitats down to 15 meters, but also occurs in deeper offshore waters. It is an oviparous species that forms breeding pairs.
