Tritoniopsis elegans is a slender nudibranch growing to about 5 cm (2 in), with several pairs of dendritic (branching) cerata and rhinophores tipped with short tentacles.

It is found on shallow water reefs, normally on the soft corals on which it feeds, but it is nocturnal and so is easily overlooked.

[4] In 2007, T. elegans was observed in Hawaii for the first time, having not been included in any previous surveys of marine invertebrates on the islands.

[7] The only other known predators on this coral are the aeolid nudibranch Phyllodesmium poindimiei and the bearded fireworm Hermodice carunculata.

[7] Tritoniopsis elegans also feeds on the Chinese octocoral Cladiella krempfi, and it has been found that the unusual diterpenes present in that coral accumulate in the nudibranch's mantle.