Buried in sand until it moves, and it secretes a milky fluid that sharks will not touch.
A right-eyed sole to about 25 cm, sandy brown with a dense pattern of pale rings and dark spots that breaks up completely against sediment. It lies flat with a dusting of sand over the body and only the two eyes, set close together on the upper side, clear of it. Movement is a rippling of the fin fringe that runs the whole margin of the body, and a fish that decides to leave does so in one glide and vanishes again.
Its interest is chemical. A row of glandular pores along the base of the dorsal and anal fins secretes a milky fluid containing pardaxin, a peptide toxin which in laboratory and field tests causes sharks to release the fish and turn away, and which has been studied as a shark repellent. The related Red Sea species produces the same compound. This is a defence a diver will only trigger by handling the animal, which is reason enough not to. Recorded from the shallows to about 30 m.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.