Pleuronectiformes

Pleuronectiformes is the traditional order name for the flatfish, a group of ray finned fish whose laterally compressed body lies on one side on the seafloor with both eyes migrated to the upward facing side during development, a distinctive adaptation among vertebrates. Some current classifications instead place the flatfish as the suborder Pleuronectoidei within the order Carangiformes, and families differ in which side they lie on: members of Pleuronectidae rest on the left with eyes on the right, while Paralichthyidae lie on the right with eyes on the left, and the more primitive genus Psettodes can develop either way.