Any fish intended for cooking purposes must be in season and must be fresh. Fish is out of season and therefore not so good during the period of spawning, the flesh being watery, flabby, and without much flavor.

Fresh fish are hard when pressed by the finger, the eyes full and the gills red. If the flesh is flabby and the eyes sunken, the fish are stale and inferior. Plenty of scales on scaly fish usually indicate freshness. The spots or marks on such fish as mackerel should be clear and bright, but one of the best tests is the smell, which should be fresh and not unpleasant. The girth of a fish should be large in comparison to its length. In choosing cut fish, such as cod, halibut, and salmon, the flesh should have a fine appearance with a close grain; if it looks fibrous, loose, and watery, it is not good. Never choose fish that is bruised or has the skin broken, as it will not keep well. Fish that is frozen should be thawed by letting it lie in cold water before it is used. Do not allow it to remain in the water longer than is necessary.

Salmon should have a small head and tail, full thick shoulders, clean silvery scales, and flesh of a bright rich yellowish red.

When quite fresh there is a white curd between the flesh, which is stiff and hard; but if kept, this melts, softening the flesh and rendering it richer, but at the same time less digestible.

Trout, in spite of the difference in size, may be judged by the same rule as salmon. It will not, however, bear keeping, deteriorating rapidly.

Cod should have a large head and thick shoulders, a small tail, the flesh white and clear, and the skin silvery and clean.

Skate should be white, thick, broad, and creamy.

Mackerel must be very fresh when eaten, or it is not wholesome. The fish should be pearly white underneath, and the markings very bright and distinct. Small or medium-sized fish are the best.

Smelts should be silvery and stiff, with a delicate odor faintly suggestive of a cucumber newly cut.

Eels are best bought alive to insure absolute freshness. They should be soaked in salt and water some time before cooking. Eels are valuable on account of their nutritive properties, and as they are rich in themselves, they are best cooked and served very simply.

To skin an eel. First cut off the head. Then turn back the skin at the top, and draw it downwards, turning it outside in. Eels about two pounds in weight are usually preferred.

Herrings must be absolutely fresh to be good, and when in this state their scales shine like silver. If kept overlong, their eyes become suffused with blood, a sure sign that the fish is stale.

Halibut is a wholesome fish. It should be moderate-sized, thick, and of a white color, the skin tight and unwrinkled.

Shrimps, Prawns, Crabs, and Lobsters should be heavy for their size. The tails should clip tightly against the bodies, and spring back quickly into position when pulled out straight and then loosened. Lobsters having thick shells, broad tails, with a few black markings, are usually the best. Crabs are bad if they are light and limp.

Oysters must be eaten only when in season and they must be very fresh. The shell should close sharply on the knife when it is inserted. If the shell is a little open, the fish is not in its primary freshness, and if it remains open, the oyster should not be consumed.