Cooks often divide fish into two categories, fatty (or oily or rich) and lean. These two categories can be split again, by whether their texture is firm or flaky.
Fatty, firm fish include tuna, eels, catfish, shark, and swordfish.
Fatty, flaky fish include salmon, herring, mackerel, and sardines.
Lean, firm fish include grouper, lingcod, mahi-mahi, and striped bass.
Lean, flaky fish include cod, flatfish, and rockfish.
Shellfish aren't technically fish, but they're usually sold at the fish counter, so we've lumped them into this category.
See also: Smoked or dried fish.
Scandinavian markets sell this in tubes, so that it can be extruded onto crackers and such for hors d'oeuvres. It's relatively inexpensive, but very salty.Learn more
This is popular in Florida and the Caribbean. In other regions, your best bet is to look in Asian or Italian markets.Learn more
Eat fresh crab the day you buy it. Unopened canned crab can be stored for up to a year in a dry, cool place. Once opened, it will keep for up to two days if you wrap it well and refrigerate it.Learn more
Crayfish are very popular in Louisiana, where restaurants serve them on large platters along with bowls of melted butter. Buy live ones if you can; if not, large supermarkets sometimes stock frozen whole crayfish or crayfish tails. Get the whole crayfish if possible--most of the flavor resides in the shells. Allow one to two pounds per person.Learn more
This is a close relative of squid and octopus. You can sometimes find dried cuttlefish in Asian markets.Learn more
This category includes yellowfish = yellow croaker (pictured), corvina = spotfin croaker, drum, redfish = red drum, white sea bass, kingfish, weakfish, and spot. Substitutes: hake (tastier) OR mullet OR tuna OR red snapper OR pompano.Learn more
Found on the Pacific coast, the Dungeness is a large crab highly prized for its sweet meat.Learn more
These haven't caught on much in the U.S., but they're highly prized in Europe and Japan for their rich, firm meat and terrific flavor. Freshness is crucial, so always buy live eels. Smaller eels are more tender. This category includes conger eel = conger = anago, which are tough saltwater eels that are sometimes available in fish markets in the spring and summer, elvers = angulas = baby eels, which are about an inch long and very expensive, and freshwater eel = unagi.Learn more
This excellent Hawaiian fish tastes like a buttery halibut. Unfortunately, it contains a natural laxative and eating it can cause serious gastrointestinal distress. Because of this, several governments (though not the US) have either banned its importation or required that it be sold with warning labels. A workaround is to eat only small (four ounces or less) portions of the fish, or to bring a change of clothes if you're dining out.Learn more
These are salmon that are raised in pens in the ocean. The wild populations are known as Atlantic salmon.Learn more
flying fish roe
These fluorescent orange eggs are wonderfully crunchy and flavorful. The Japanese are particularly fond of them.Learn more
This has crunchy, amber-colored eggs and makes a colorful garnish. They're often flavored with various seasonings before they're sold.Learn more
Littleneck clams are smaller than cherrystone clams which are smaller than quahog clams = quahaug clams = chowder clams which are smaller than ocean quahog clams = ocean quahaug clams = mahogany clams = black clams.Learn more
The Japanese traditionally serve this on New Year's Day. It has an interesting texture, but it's not very flavorful.Learn more