Lunar-Tailed Bigeye

Priacanthus hamrur

The lunar-tailed bigeye (Priacanthus hamrur), also known as the moontail bullseye, is a striking nocturnal reef fish reaching up to 45 cm. It is characterized by enormous, reflective red eyes adapted for night vision and a distinctive crescent-shaped caudal fin. The body color ranges from bright red to silvery-pink depending on the fish's mood. Found across the Indo-Pacific from the Red Sea and East Africa to French Polynesia, it inhabits outer reef slopes, rocky areas, and lagoons at depths of 8 to 250 meters. During the day it shelters in caves and under ledges, emerging at night to feed on zooplankton, small fish, and crustaceans. It can rapidly change color from deep red to pale silver. Divers frequently encounter small groups hovering near cave ceilings during daytime dives, making it a reliable and photogenic sighting on reef wall dives.