Black Back Butterfly Fish

The black butterflyfish has a darkish bluish-grey body with a contrasting white mouth, and a narrow yellow band on its snout. There is a dark darker bump on the forehead. The dorsal, anal, and caudal fins are yellow. There is an orange band which runs across the dorsal and anal fins and across the caudal peduncle, these fins also have black margins, as does the tail. Juveniles have paler grey bodies and yellow median fins. The dorsal fin has 12-13 spines and 24-27 soft rays while the anal fin has 3 spines and 20-21 soft rays. This species reaches a maximum total length of 20 centimetres (7.9 in).