The Half-moon Triggerfish (Sufflamen chrysopterus) is also commonly referred to as the Flagtail Triggerfish or the Yellow-backed Triggerfish. This species is found in the warm tropical waters of the Indo-Pacific region and in Australia is in found from Coral Bay in Western Australia around the north to Sydney in New South Wales. There is a very large difference in appearance between adults and juveniles. Juveniles have a white underbody with the upper half separated by a black line that runs across the eye and has yellow colouration on top covering the dorsal fin. Adults are a dark colour all over with red markings at the base of 2nd dorsal fin and anal fin and blue colouration underneath the front part of its head.
Juveniles of this species are often found on semi protected coastal reefs and adults can be found on offshore coastal reefs to depths of 20 metres. The Half-moon Triggerfish (Sufflamen chrysopterus) grows to a maximum length of approximately 30cm.
