Lefteye flounders are a family of very flat fish which lie on the seafloor on their right sides, with both their eyes on their left sides. It is possible, but highly rare, that this is reversed in some specimens. This family is also noted for having spines near the eyes and on the snout. Some species have tentacles on the eyes. Species size varies from 4.5 cm up to 88 cm.
Noticeably, there are no spines in the fins, all of the fins are soft rays. The dorsal fin starts above the upper eye. The anus is located on the bottom 'blind' side of the fish.
The eye side of lefteye flounders usually has spots, blotches or rings, with the blind side being usually a light colour (except a dark colour for males in a limited few species). These fish are predators of bottom-dwelling invertebrates and small fish.