Walks on the sand on stiffened fin rays and opens two blue-spotted fans when pressed.
A heavy-headed fish to about 40 cm, encased in a bony helmet with a long spine projecting backwards from each cheek, and coloured in mottled sandy brown that is unremarkable until the fish opens up. The pectoral fins are enormous — as long as the body — and marked with rows of bright blue spots and lines on a dark ground. Folded, they lie flat and invisible along the flanks.
It does not fly and does not glide. The front rays of each pectoral are separate and stiffened, and the fish uses them to walk over the bottom, picking at small crustaceans and molluscs in the sediment; the fans are spread as a threat display when it is followed, and to startle a predator. That display is what everyone photographs, and getting it means following the fish steadily rather than rushing it — a fish that is chased simply swims. Recorded from the shallows to about 30 m on open sand. Juveniles are smaller, rounder and proportionally more spectacular when they open.
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.