Fish
Fish should always be perfectly fresh when cooked. To select fresh ones observe the eyes; if they have a bright life-like appearance the fish is fresh; if, on the contrary, the eyes are sunken and dark colored, and have lost their brilliancy, they are certainly stale. Some judge by the redness of the gills, but they are sometimes colored to deceive customers.
Crabs should be of a dark green color, and when fresh from the water are always very lively, the same remarks hold good with regard to lobsters. If the tail of the lobster will return to its former position when pulled out, the lobster is fresh.
Never buy a clam or oyster if the shells are parted. If the valves are tightly closed the oyster is fresh.