The largest eastern Pacific triggerfish, grey-brown and heavily built, over rock and sand.
To 76 cm, commonly 50, which makes it one of the largest triggerfish anywhere. Olive-grey to brownish with a bluish or purple sheen on the head and blue lines and spots on the snout and around the eye. The name is misleading: the scales are large, thick and clearly visible. Large adults grow trailing filaments from the tail lobes.
The orangeside triggerfish is the confusion and one mark separates them: that species has a thin oblique yellow bar running from the corner of the mouth across the lower cheek, and it is smaller and more oval. This one is much bigger and has no yellow cheek bar.
It lives on rocky reef and boulder slopes between 3 and 60 m. Adults are on the bottom and juveniles are up in the water column. It builds a nest in sand and guards it, and it is large and powerful enough that a diver who approaches a nest can be charged and bitten. At Revillagigedo it has been recorded at Sulphur Bay on Clarión and on Socorro, with museum specimens going back to 1925.
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.