The eightband butterflyfish (Chaetodon octofasciatus) is a small reef fish easily recognized by its light-colored body marked with black bands. It lives in tropical waters of the Indo-Pacific, always close to coral reefs.

This butterflyfish is closely associated with the corals it feeds on almost exclusively. Adults are generally observed in pairs in sheltered lagoons and on reefs near the coast, while juveniles often live among colonies of corals of the genus Acropora, which provide them with both food and shelter.

The eightband butterflyfish has a short, deep, strongly laterally compressed body, characteristic of butterflyfish. Its light-colored, white to yellowish coloration is crossed by eight vertical black bands that run across the head and sides. The first passes through the eye, while the others are distributed across the body and extend to the tips of the dorsal and anal fins. A dark band also marks the snout.

The eightband butterflyfish is a small species that reaches a maximum length of 4.7 inches.

The eightband butterflyfish inhabits tropical waters of the Indo-Pacific, ranging from Southeast Asia and the Philippines to Papua New Guinea, the Great Barrier Reef, the Solomon Islands, and Palau, and northward to the coast of China.

In the Indian Ocean, it is found in the Maldives, Seychelles, India, and Sri Lanka.

The eightband butterflyfish mainly inhabits coral reefs, sheltered lagoons, and coastal areas rich in corals, generally between 10 and 66 feet deep. It remains close to coral colonies, which provide both its habitat and its main source of food.

Adults are generally observed in pairs, while juveniles may gather among Acropora colonies, which provide them with shelter and a source of food.

The eightband butterflyfish has a highly specialized diet. It feeds almost exclusively on coral polyps, which it picks directly from colonies with its small, specially adapted mouth.

This dependence on corals explains its close association with coral reefs. It moves among coral colonies in search of the polyps on which it feeds.

The eightband butterflyfish is an oviparous species: the female releases her eggs into the open water, where they are fertilized. Adults reproduce in pairs, a behavior observed in several butterflyfish species of the genus Chaetodon.

Because coral polyps make up most of its diet, the eightband butterflyfish is particularly dependent on the health of coral reefs.