The most venomous fish there is, and it looks exactly like the rock beside it.
A heavy, warty fish to about 40 cm with an upturned mouth, eyes set high on the head and skin usually carrying encrusting algae and sediment. It differs from the estuarine stonefish in having no deep hollow between the eyes and in living on hard substrate — rubble, rock and reef base — rather than on silt. Colour is whatever it is sitting on, and the animal is genuinely invisible until it moves or until a light catches the eye.
Thirteen dorsal spines, each fed by a pair of venom glands, and the most potent fish venom known; a sting is a medical emergency requiring immediate care, and hot-water immersion is the standard first response while that is arranged. The fish does not flee, because its whole strategy is not to be seen, so a diver’s hand or knee is the usual way people are stung. The practical rule on a muck site is the same one that protects everything else: nothing goes on the bottom that has not been looked at first. Feeds by ambush, taking small fish with a strike measured in milliseconds.
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.
