Rhytisma fulvum is a zooxanthellate species and has two different colour morphs, yellowish-brown and grey.

Its range extends from the Red Sea, Zanzibar and Madagascar, to Indonesia, Papua New Guinea and the Great Barrier Reef in Australia.

[3] Rhytisma fulvum is a dioecious species of soft coral, colonies being either male or female.

Each polyp in a female colony produces about twenty eggs, which is a relatively low number, but this is compensated for by the brooding process which maximises the chances of the developing larvae avoiding predation.

[2] The appearance of this seaslug closely resembles the surface of the coral, its gills even mimicking the feeding polyps, and this makes it very well-camouflaged.