Ceratosoma tenue

Images taken at Mooloolah River, QLD, Australia

Ceratosoma belong to the family Chromodorididae. The body is usually smooth, elongate-ovate in shape with undulating mantles with mantle glands at the posterior end or to elaborate appendages behind the gill. The mantle glands store its defensive mechanism, a toxic chemical obtained from the sponges it feeds on. The rhinophores and gills are able to retract into pockets. The rhinophores are lamellate clubs.

Colour is variable ranging from pale yellow through to darker orange and reds with a variety of different colour spots. A tall appendage behind the gills contains a defensive mechanism of toxic chemicals that it stores from its food source that has a purple margin. The edge of the lobes and ridge joining the posterior lobes are outlined with a blue/purple line.