The spots are rings with pale centres, which is what separates it from the netted species.
A dorid to about 6 cm, the mantle firm and white to cream, scattered with reddish-brown to maroon marks, many of which are rings with a paler centre rather than solid spots, and bordered by a band of pink to purple with a fine pale edge outside it. Goniobranchus reticulatus carries a continuous network of red lines rather than separate marks, which is the quickest separation. The genus holds a number of spotted white species, and the working characters are whether the marks are rings or solid and what colour the marginal band is; neither survives a soft photograph.
Feeds on sponges and stores their defensive compounds in glands around the mantle rim. Recorded across the western Pacific from Indonesia and the Philippines to the Great Barrier Reef, on sponge-covered rubble and rock from about 8 to 30 m. It is not a silt animal: on a muck site it turns up on the harder ground at the ends of the slope rather than out on the open sand.
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.
