Indonesian Sweetlips

Found singly or in small schools, during the day close to large caves and walls, of deep reefs dispersing at night hunting for food.
They feed nocturnally on benthic crustaceans, fish, and invertebrates.
Juveniles close to outcrops over estuaries and silty reefs.

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.