Yellowtail Coris

Overview

The Yellowtail Coris (Coris gaimard) is a solitary, reef-associated wrasse known for its dramatic transformation in appearance as it matures. It is commonly found in tropical Pacific waters, inhabiting areas with a mix of coral, sand, and rubble across reef flats and lagoons.

Distribution & habitat

This species is widely distributed throughout the Pacific Ocean, ranging from Christmas and Cocos-Keeling Islands in the eastern Indian Ocean to the Society and Tuamotu Islands, extending north to Japan and the Hawaiian Islands, and south to Australia. It typically occupies shallow waters at depths between 0 and 50 meters.

Appearance

The Yellowtail Coris undergoes a striking color change throughout its life. Juveniles are bright red-orange with distinctive white, black-edged saddle blotches. As they mature, they transition into a slate blue-green body covered in turquoise spots, featuring a characteristic bright yellow tail and a green-tinted face. Adults may reach up to 40 cm in length.

Biology & behavior

This species is a protogynous hermaphrodite, meaning individuals are born female and can transition into males as they grow. They are known for their habit of burying themselves in the sand to sleep at night or when threatened, requiring a deep, fine sandy substrate to avoid injury. They are generally solitary and independent in their behavior.

Feeding

As an active carnivore, the Yellowtail Coris uses its strong teeth to hunt for prey. Its diet consists primarily of mollusks, crabs, and hermit crabs, though it may also consume tunicates and forams. It is often observed foraging through rock crevices and turning over gravel in search of food.