Identification:
The body is tall and distinctly laterally compressed. The head is small, with a very long snout, measuring 33-38% of the body length. The caudal fin is rounded and convex. The body from the origin of the dorsal fin and pectoral fin base to the caudal fin base, including the dorsal fin, pectoral fins, pelvic fins, and anal fin, is bright yellow. The posterior margin of the soft portion of the dorsal and anal fins is blue. At the end of the anal fin base, there is a large, round black spot, equal in size to the eye’s diameter. From the origin of the dorsal fin and pectoral fin base forward, the body has two colors: the dorsal half and snout are black, and the ventral side is grayish-blue. The caudal fin is grayish-blue. Occasionally, individuals of a uniform dark brown color are observed.
Biology and Ecology:
This species inhabits coral reefs, often found in pairs or small groups of 3-4 individuals on the outer slopes of the reef. It feeds on organic debris, zooplankton, and particularly small crustaceans. It is commonly found at depths of 5-60 meters. The largest recorded individual reached 17.9 cm.
Distribution:
- Vietnam: Khánh Hòa province, the Gulf of Thailand, and the Spratly Islands.
- Worldwide: Japan, China, India, Australia, Hawaii, Indonesia, the Philippines, Thailand, East Africa, and the Red Sea.
Value:
This species has limited food value due to its small size, scarcity, and relatively poor flesh quality. However, it can be kept in aquariums as an ornamental fish due to its beautiful coloration.
Conservation Status:
Before 1995, this species was frequently encountered at Hon Mun and other coral reefs in Nha Trang Bay and the Spratly Islands. In recent years, it has become rare, with very few sightings. The reasons for this decline may include active harvesting for sale. Furthermore, the exploitation of aquatic resources using explosives and toxic chemicals, as well as environmental pollution, has resulted in habitat loss and the overall reduction of aquatic resources.
IUCN Classification: VU A1d B2b+3c.
Conservation Measures:
This species should be included in the list of protected species managed by the fisheries sector. It is recommended to prohibit the catching and trade of this fish for sale.