Chaetodon octofasciatus Bloch, 1787

Species Naming & Body Shape

The eightband butterflyfish (Chaetodon octofasciatus Bloch, 1787) has a flat, circular disk-shaped body with a slightly pointed snout.

Base Body Coloration

Its body is white, fading to yellowish toward the belly, and marked with 7 black stripes across the head and flanks.

Stripe Placement

One stripe runs centrally along the snout, another forms a distinct black margin along the dorsal and anal fins, and the third stripe extends onto the pelvic fin.

Fin Color

All fins are yellow.

Caudal Peduncle Marking

There is a black spot ringed with white on the caudal peduncle.

Variable Body Markings

Some individuals have black or brownish horizontal bars that connect the rearmost pairs of vertical bars.

Environment-Linked Color Variation

The fish's background color varies based on the environment it lives in: paler, cream-colored individuals occur in clear waters over coral reefs, while yellower individuals are found in less clear, algae-tinted green water near river mouths.

Fin Ray & Spine Counts

The dorsal fin has 10-12 spines and 17-19 soft rays, and the anal fin has 3-4 spines and 14-17 soft rays.

Species Size

This is a relatively small butterflyfish species that reaches a maximum total length of 12 centimeters (4.7 inches).

Geographic Distribution

The eightband butterflyfish is distributed in the eastern Indian Ocean and western Pacific Ocean, ranging from the Maldives, India, and Sri Lanka east to the Solomon Islands, north to southern Japan, and south to the Scott Reef in Western Australia.

Habitat Depth Range

It inhabits coral reefs at depths between 3 and 20 meters (9.8 and 65.6 feet).

Habitat Segregation by Age

Adult eightband butterflyfish swim in pairs in coral-rich areas of sheltered inshore and lagoon reefs, while juveniles are often found in groups among Acropora corals.

Diet

This species feeds exclusively on coral polyps.