Lesson's Thicklip

Found singly during the day, close to caves and ledges of steep slopes, dispersing at night to hunt for food over outer reef lagoons.
They feed nocturnally on benthic invertebrates.

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.