Another nudibranch of the chromodoris family with white, yellow, and purplish/blue/brown as its signatory colours.  It does differ significantly from its look-a-likes however, due to its all-white gills and more brownish rhinophores.  It also seems to be far less common — likely due to its nocturnal nature and preference for dark shady spots.  The Imperial, Trembling and Tom Smith are all diurnal species, more likely to be found wondering about shallow,, rocky, sponge-covered reefs in broad daylight.