Body strong and stout, with a large mouth. Body brownish to gray. Can pale or darker. Small whitish blotches over the upper body and fins and pale scrawled markings on the belly (M. rubra). Three to four dark lines extend from the eye and cheek to just beyond the gill cover. Markings become less distinct with age.
Size up to 144 cm.
Occurs over rocky and sandy bottoms, down to 40 m. Young individuals very common in mangrove-lined lagoons. Feeds on mollusks and small fish that are drawn into their gullets by a powerful suction created when they open their large mouths. Held securely by thousands of small, rasp-like teeth that cover the jaws, tongue and palate, the prey is swallowed whole. Groupers are hermaphroditic, beginning life as females, but changing to males with maturity.
Common southern Caribbean, rare in the north.