Spot-tail Grunt

Found in large schools during the day, dispersing at night, foraging for food, over open, sandy, coastal reefs.
They feed nocturnally on small fish and molluscs.
Juveniles found over seagrass beds.

In some areas of the world 'Grunts' are better known as 'Sweetlips' distinguished from other species by their very large rubbery lips.
'Grunts'because they "grunt," the grunting sound is produced by their flat teeth plates rubbing together and this is amplified by their air bladders.
Found either singly or in schools hovering or motionless over the reef during the day, becoming nocturnal predators.