Sits as a lump of algae-covered rock until it flashes the orange inside of its pectorals.
A stocky scorpionfish to about 30 cm with a pronounced hump on the back behind the head, from which one of its English names comes. The body is covered in skin flaps, warts and filaments and is coloured to match encrusted rock — grey-green, red, brown or mottled cream — and an undisturbed fish is genuinely difficult to resolve as an animal at all. The inner surfaces of the pectoral fins are bright orange-yellow with a black and white margin, hidden entirely when the fins are folded.
Those pectorals are the identification. Disturbed, the fish lifts and spreads them for a second or two, showing the colour, and then settles again; the display is a warning and it is the quickest way to separate this species from the several other Scorpaenopsis on the same ground. It is also the origin of “false stonefish” — it is regularly mistaken for Synanceia, which is a different family, blunter still and far more dangerous. Recorded from the shallows to about 40 m, usually on rubble and rock rather than open sediment. Venomous dorsal spines; the fish does not move for a diver, so the diver moves.
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.
