It is a marine gastropod mollusc in the family Tritoniidae.The genus was described in 1907 by the British diplomat and malacologist Charles Eliot.

[1] Tritoniella can be differentiated from Tritonia (the only other Tritoniidae sharing its distribution range) by a wide dorsal ridge and lack of foliaceous tufts (gills).

The colour is variable, ranging from a translucent milky white to yellow or orange.

[3] Tritoniella belli incorporates the chimyl alcohol ingested from Clavularia frankliniana into its tissue to use it as a chemical defence to make itself upalatable against predators.

[3] It is avoided by the predatory starfishes Odontaster validus, Perknaster fuscus and Acodontaster conspicuus because the mucus it extrudes is distasteful; it is preyed on by the sea anemone Isotealia antarctica, but 70% of the encounters between the two result in the nudibranch escaping, or the sea anemone swallowing the nudibranch but then regurgitating it from its gastrovascular cavity.