The largest porcupinefish, pale with small dark spots and long spines that lie flat until it inflates.
To 91 cm, commonly 40, which makes it the largest porcupinefish in the world. The body is heavy and inflatable and covered in long sharp spines that lie folded backwards when the fish is not inflated. Greyish-tan to olive-brown above and white below. The identification is the spotting: small black spots cover the head, the body and the fins. There is no dark bar through the eye and no large blotch anywhere; the spotting is fine and even.
The balloonfish is the confusion, and the fin spots are the cleanest single check — this fish has them and the balloonfish does not. The balloonfish also has longer spines and dark blotches with a bar through the eye, and reaches about half the size.
It is nocturnal and spends the day motionless in a cave, under a ledge or in a wreck, which is where divers find it. At night it crushes molluscs, urchins, hermit crabs and crabs with its fused beak. It lives between 2 and 50 m and usually between 3 and 20. Juveniles drift in open water.
It is poisonous to eat. The real diver hazard is the beak: this is a large animal with jaws built to break open sea urchins, and it can take a finger off. Do not hand-feed it and do not handle it, and do not provoke inflation.
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.