Rostanga aliusrubens is a species of sea slug, a dorid nudibranch, a marine gastropod mollusc in the family Discodorididae.
This species was described from Darwin, Northern Territory, Australia.[1]
This dorid nudibranch is red and the dorsum is covered with caryophyllidia; it is very similar to other species of Rostanga.
Rostanga aliusrubens is found on the red sponge, Clathria lendenfeldi (family Microcionidae) on which it presumably feeds. Most other species of Rostanga also feed on sponges of the family Microcionidae.