This large subclass of saltwater fish, encompassing some 500 species (130 available in the U.S.), includes popular varieties like flounder, halibut, sole and turbot. Most of these fish have sweet, delicate white flesh that chefs and consumers everywhere enjoy: low fat, fine-textured meat and mild flavor. All flatfish belong to the order Pleuronectiformes, which means they have both of their eyes on the same side of their head.
All flatfish start out life looking like normal fish, but after a few weeks, one eye migrates to the other side of their head, their bodies flatten into an oval shape, one side turns dark and one side white, and they settle to the bottom of the sea floor. The meat from a flatfish typically varies in color: fillets from the bottom (white) side of the fish will be thinner and whiter, while fillets from the top (dark) side will be thicker and more gray. Even though many of them are called soles, all the flatfish fished commercially in the U.S. are really flounders. To show the extent of the confusion:
- Pacific Dover Sole, a flounder not the same as true English Dover Sole from the North Atlantic, is the most common flounder sold on the West Coast.
- Yellowfin sole is a small flounder.
- Arrowtooth flounder, which is found from California to Alaska, has a soft flesh and is often marketed as “turbot,” although it is not European turbot, the most expensive flatfish in the world.
- Greenland turbot, which is caught in both the North Atlantic and North Pacific oceans, is not really a turbot either, but instead is a member of the halibut family. Outside of North America, it is called Greenland halibut or black halibut. To avoid marketing confusion with Pacific halibut, the halibut industry successfully lobbied to have the name of this flatfish changed to turbot.
- California halibut is actually a left-eyed flounder.
- Fluke is a common name for summer flounder, a popular East Coast flatfish that occurs from the southern Gulf of Maine to South Carolina. Because it is a closely related species, California halibut may also be called fluke on occasion. It’s enough to make someone flounder, or at least try one’s sole.