[1] The Paralichthyidae are the opposite, with their eyes on the left side.

A small number of species in Pleuronectidae can also have their eyes on the left side, notably the members of the genus Platichthys.

Females lay eggs that float in mid-water until the larvae develop, and they sink to the bottom.

The smaller species eat sea-floor invertebrates such as polychaetes and crustaceans, but the larger righteye flounders, such as H. hippoglossus, which grows up to 4.7 m (15 ft) in length,[6] feed on other fishes and cephalopods, as well.

They include many important commercially fished species, including not only the various fish called flounders, but also the European plaice, the halibuts, the lemon sole, the common dab, the Pacific Dover sole, and the flukes.