a.k.a.: Crawdads, crawfish; there are over 400 varieties of crayfish including Red Swamp Crayfish, White River Crayfish, Pacific Crayfish. Crayfish should not be confused with spiny lobsters or saltwater crayfish which are of a different species.

Waters:Crayfish are found only in fresh waters, usually in streams, creeks and lakes. Crayfish can be found around the world; many American crayfish are fished for in Louisiana ("crawfish capital of the world"), California, and Oregon.

Description (in water): Crayfish look like miniature lobsters, complete with claws and antennae. They range in size from 3 to 6 inches in length and weigh between 2 and 8 ounces.

Description (in market): Crayfish should always be bought live and should look exactly as they do in water. However, one can also buy soft-shell crayfish (similar to soft-shell lobsters which have shed their shell and have yet to grow a replacement) which are sold in vacuum packed containers.

Sold as: Live, frozen, or vacuum-packed soft-shell variety.

Best cooking: Crayfish are most often cooked by throwing them (live) in a pot of boiling water and simmering for 5 to 8 minutes. All kinds of spices and herbs can be added to the water; Scandinavian traditions favor bunches of dill; the French like vegetables (e.g.. carrots, onions, celery) and herbs (such as tarragon and parsley) and perhaps a little wine; Creole spices are preferred in Louisiana. The crayfish are served either hot or cold, still in the liquid which was used to cook them. Crayfish, like lobster, are eaten with the hands; a juicy, messy treat best savored by sucking the meat out of the tail. The soft-shell variety can be eaten whole, but for the two calcium stones (called gastroliths) used to create a new shell. To remove them, snip off the eyes and mouth and squeeze out the two stones.

Buying tips: Buy them live. Ask to see them before your fishmonger picks them out for you. Dead crayfish will not be fresh. It's possible to buy whole crayfish frozen but you're best off with the live version.

Substitutes: Shrimp or lobster meat.