This species spends its entire life cycle(holeopelagic) at the oceans surface, attached by
the foot to a raft of mucus covered bubbles. It is carnivorous, preying on pelagic Cnidarians
such as Porpita sp, Velella velella and Physalia sp(Bluebottle). This is the largest and
commonest species found on Australian beaches but has an almost worldwide distribution.

Image above shows mating pair, with white sperm being passed to female. Janthina janthina
is the intermediate host of a parasitic copepod, Cardiodectes, of the family Pennellidae. These
are parasitic on fish and may be the tiny dark animals on the body of the snail.

Image below shows veliger larvae being released

Overgrown with Lepas pectinata

Feeding on Physalia

© All images Copyright 2019 Denis Riek. All rights reserved.