Fish ID: Lined Butterflyfish

Butterflyfish lined ci fci
Family Butterflyfish (CHAETODONTIDAE)
species Chaetodon lineolatus
size Up to 30cm
locality Outer reefs
behaviour Doesn't cling to the reef like smaller Butterflyfish
range Throughout the Indian Ocean to the Pacific

Largest of the Butterflyfish.  There are others with vertical lines, but this one has a single black bar across the eye, and another which extends from the top of the back to, and including, the base of the tail (caudal peduncle).