The Ornate Butterflyfish (Chaetodon ornatissimus)

by B. N. Sullivan

Fishes in the Butterflyfish family (Chaetodontidae) are among the prettiest inhabitants of tropical reefs around the world.  This species, the Ornate Butterflyfish (Chaetodon ornatissimus) is particularly nice looking, we think.

The Ornate Butterflyfish is easy to recognize, with six diagonal yellow-orange stripes on each side of its creamy body, black and yellow bars on the face (including one that covers the eye), a gray patch on its forehead, and black 'trim' around its margins.  They are said to grow to a length of 20 cm (about eight inches), although most of the adult individuals we have seen are somewhat smaller -- usually about 15 cm (six inches).

C. ornatissimus feeds exclusively on live coral polyps, so you would expect to find them in coral-rich areas. They seem to favor coral polyps of the Pocillopora and Montipora genera.  (Here in Hawaii, we frequently see them pecking on Pocillopora meandrina.)

Juveniles of this species look like cute miniatures of the adults.  The juveniles can be quite shy, hiding in corals for protection.  The juveniles live as singletons, but once they reach breeding age, they find mates and form pairs.  In fact, it is unusual to see an adult of this species not accompanied by its mate.  Also, pairs establish a home range, so once you discover a pair of C. ornatissimus, you will likely be able to find them again in the same area time after time.

'Ornates' are an Indo-Pacific species, most commonly found in the central and western Pacific, from Hawaii to Australia's Great Barrier Reef.  Sightings have been reported as well around Christmas Island in the eastern Indian Ocean, and we have seen photos of the species taken in Indonesian and Malaysian waters.  They are quite common here in Hawaii. I photographed the one pictured on this page in Honaunau Bay, on the south Kona coast of Hawaii's Big Island.