GroupersEpinephelidae

Groupers are robust, predatory fish, typically distinguished by a heavy, often slightly compressed body, a large head, and thick, fleshy lips. Their prominent mouth can protract rapidly to create a powerful suction, drawing in prey. Three flat spines are present on the gill cover. Members of this group display a wide size range, from small hinds around 20-25 cm (8-10 in) to the Giant Grouper, which can reach 2.5 m (8 ft) in length and exceed 200 kg (440 lb). Many species exhibit the ability to rapidly change their colour and pattern, shifting within seconds from pale to barred or mottled, a trait reflected in the genus name Epinephelus, meaning "clouded over".

Most groupers are solitary, ambush predators commonly found motionless under reef ledges, within wrecks, or at cave mouths. They inhabit diverse reef environments from shallow patch reefs to deep reef slopes and drop-offs, typically down to 100 m (330 ft), though some species range deeper. Their diet consists primarily of fish, crabs, and octopus, which they consume with a swift lunge. A notable behaviour among some, such as the Roving Coralgroupers, involves hunting cooperatively with moray eels; they recruit an eel by shaking their head in front of it, prompting the eel to flush prey from crevices inaccessible to the grouper. Nearly all groupers are protogynous hermaphrodites, beginning life as females and later transitioning to males.