a.k.a.: Flounder, halibut, fluke, sole, dab, sand dab, turbot, brill, plaice (all of these are members of the flatfish family)

Waters:Atlantic and Pacific coasts

Description (in water): "Flatfish" can refer to any member of a species of thin, flat fish that swim on one side; both eyes are located on the side that faces up. Size and color vary depending on the species; the downward-facing side of the fish is always pale and nearly colorless.

Description (in market): In general, flatfish have lean white or off-white flesh that's fine-textured and mild in flavor. The skin is edible, and usually quite tasty.

Sold as: Whole, fillets, steaks

Best cooking: Whole flatfish can be broiled or grilled (you'll need to use a grill basket); the scales are small and can be scraped off. You can do almost anything with flatfish fillets, which are particularly good seasoned, flour-dredged, and pan-fried. Fillets should be cooked briefly (less than 5 minutes)--be sure not to overcook them, or they'll dry out and fall apart. Once the fillet turns opaque white, it's done.

Buying tips: Whole fish should have red, alive-looking gills and bright, unmarred skin. Fillets and steaks should glisten and be free of browning and signs of drying. Make sure to smell for freshness.

Substitutes: The members of the flatfish family are pretty much interchangeable; cod, haddock, and whiting are additional options.