Buy only from reputable sources. Be wary, for example, of vendors selling fish out of the back of their pick-up trucks.
Buy only fresh seafood that is refrigerated or properly iced.
Don't buy cooked seafood, such as shrimp, crabs or smoked fish, if displayed in the same case as raw fish. Cross-contamination can occur.
Don't buy frozen seafood if the packages are open, torn or crushed on the edges. Avoid packages that are above the frost line in the store's freezer. If the package cover is transparent, look for signs of frost or ice crystals. This could mean that the fish has either been stored for a long time or thawed and refrozen.
Put seafood on ice, in the refrigerator or in the freezer, immediately after buying it.
Recreational fishers who plan to eat their catch should follow state and local government advisories about fishing areas and eating fish from certain areas.