Butterflyfish; Western

Chaetodon assarius

The butterfly fishes are a group of about 120 species that are mainly restricted to coral reefs.  The western butterflyfish is one of only three species to complete their lifecycle in temperate Australian waters.  They have a very deep compressed body, a characteristic pointed snout and brush-like teeth.  The species is creamy white dorsally to white ventrally, with a series of small dark spots forming at least four vertical stripes down the body.  They have a brownish dusky anal fin with a white margin and juveniles have a white-edged black ocellus (or “false eye”) on the dorsal fin, which is reduced to a dark spot in adults.  The species grow to a maximum length of 13 centimetres.

The western butterflyfish are endemic to the subtropical waters of Western Australia, and are common north of Perth.  They inhabit coastal reefs and feed on a variety of small invertebrates, including hard and soft coral polyps.

Occurrence at the Busselton Jetty:

The western butterflyfish is a common visitor to the waters surrounding the Busselton Jetty.