Spines flat until they are not; usually found asleep under a ledge by day.
To about 65 cm, pale brown above and white below with large dark blotches edged in white, including a broad band through the eye, and short spines that lie flat against the body when the fish is relaxed. Diodon hystrix is larger, covered in small dark spots rather than blotches, and has longer spines.
It shelters under ledges and in crevices through the day and hunts hard-shelled invertebrates at night, crushing them with fused plate-like teeth. Inflation is a defence that should not be provoked; a fish backed into a corner by a diver will do it, and it takes a long time to recover. A resting fish photographs well because it stays put, though the eye is usually the only part not in shadow. Recorded from about 3 to 40 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.