The harlequin sweetlips fish

These fish have big, fleshy lips and tend to live on coral reefs in the Indo-Pacific in small groups or pairs. They will often associate with other fishes of similar species; several species of sweetlips sometimes swim together. They are usually seen in clusters in nooks and crannies or under overhangs. At nightfall, they venture from their shelters to seek out their bottom-dwelling invertebrate prey, such as bristleworms, shrimps, and small crabs.

Sweetlips colouring and patterning changes throughout their lives. For example, Plectorhinchus polytaenia develops more stripes with age. Juvenile sweetlips generally look quite different from the adults, and often live solitary lives on shallower reef sections. Juveniles may be banded or spotted and are usually a completely different colour from the adults of their species. Small juveniles have an undulating swimming pattern, possibly mimicking poisonous flatworms as a means of predator avoidance.