A large puffer in two colour forms, black covered in white spots or bright plain yellow, on eastern Pacific reef.
To about 40 or 50 cm depending on the source. There are two colour forms and they are so different that divers log them as two species, so they need setting out. The common form is black to very dark brown covered in numerous small white spots, which sometimes join into wandering white lines; that is the guineafowl pattern the name comes from. The other form is uniform bright yellow, sometimes with irregular black patches, and it is frequent at some eastern Pacific sites. Blotched black-and-yellow individuals occur, which is how it is known they are one species.
The body is heavy, rounded and inflatable with a blunt head, a short snout, powerful fused jaws, no pelvic fins and no fin spines, and skin covered in fine prickles. In the eastern Pacific there is no confusion, because it is the only puffer of its genus there.
It lives on coral and rocky reef between 1 and 80 m, near the bottom. It bites the tips off living coral, and also eats sponges, molluscs, tunicates and algae. It is slow, unafraid and easily approached, which is why it is so often photographed and so often harassed into inflating. It is poisonous to eat and has a strong beak, but it presents no contact hazard.
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.