Although fish may have been cleaned and dressed at the market, they are likely to need additional cleaning before they are cooked.
If any scales have been left on a fish that is to be cooked with the skin on, remove them with a dull knife (a sharp one might cut the skin).
Draw the knife over the fish, from tail to head, slanting it toward the body of the fish at an angle of about 45. If the fish is to be split, remove the head and tail.
Wash quickly under cold running water and wipe the fish thoroughly, inside as well as outside, with a wet cloth. Then wipe with a clean dry cloth and keep on a plate in a cold place until ready to use.
Lay the fish flat on work surface. Rub a scaling tool or the back of a knife against the scales from tail to head. Repeat until all scales are removed. Rinse. (Exceptions: Trout, with very tiny scales, and scaleless fish, like catfish, are not scaled.)
Slit the belly and pull out viscera. Rinse cavity.
Scissors are easiest to use.
Cut through flesh just behind gills. Cut or break backbone at the cut and pull off head.
The thicker the slices, the longer they will retain their heat. Thin slices draped into a fan will need to be served immediately, if that is your aesthetic preference. It is a question of personal taste, but I would leave a little meat on the wing when carving chicken, to make a more substantial portion.
Clean and skin the fish. Insert a sharp knife close to the backbone at the tail end, and cut the flesh from the bone, working toward the head and keeping the knife as close as possible to the bone. Small bones that adhere to the flesh or are embedded in it must be removed with the fingers.
Large fish, such as cod and halibut, are easily boned; in fact, they are usually purchased in slices. Fish with many bones, like shad, can not be boned satisfactorily.
Flounders are often boned, to form fillets, and are served as "fillets of sole." The English sole is seldom imported, and most of the "fillet of sole" that is served in America is made from the flounder, which has a white, delicate flesh similar to the sole.
A fillet is merely a piece of fish without skin and bones. Fillets look better on the serving platter if they are approximately the same size. Rolled fillets are called turbans. They are fastened with wooden toothpicks to keep them in shape during cooking, but the picks are removed before the fish is served.
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