Bothidae (lefteye flounders)
Pleuronectidae (righteye flounders)
Achiropsettidae (southern flounders)
Achiridae (American soles)
The flatfish are an order (Pleuronectiformes) of ray-finned fish, also called the Heterosomata, sometimes classified as a suborder of the Perciformes. The name means "side-swimmers" in Greek. In many species both eyes lie on one side of the head, one or the other migrating through during development.
Many important food fish species are in this order, including the Dover sole, flounder, plaice and halibut.