A white chromodorid with black lines and an orange margin, from the west and south coasts.
To about 6.5 cm. The ground is black, carrying one or two vivid blue patches finely speckled with darker dots, and the whole is bordered by an orange band. The rhinophores and gills are deep orange-red. It varies: the black may form a band against the inside of the orange margin or be separated from it by white or bluish gaps, and the black patch splitting the blue area is sometimes absent.
One Indo-Pacific species is very similar in its speckled blue area, and it has been suggested that this animal evolved from it in Western Australia. That species has a mantle striped lengthways in white, blue and black with a yellow-orange margin, where this one has discrete blue patches on black. Several similar undescribed forms exist in Western Australia, so treat the group as unsettled.
It eats a single species of sponge and stores its chemicals for defence, which is what the colours advertise. It lives on shallow, partly exposed reef down to about 18 m.
It is endemic to Western Australia, from the Kimberley south to Esperance, including the Abrolhos, Rottnest Island and Ningaloo, and is particularly common near Perth. It does not occur on the east coast.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.
