To scale a fish: grasp it by the head (or lay it on a board and drive a fork through its tail), and, using a knife that is not over-keen, scale first one side and then the other, with swift, steady sweeps. The scales below the gills, and those near the fins, are removed by moving the point of the knife crosswise to the fish's length. Next place the knife just below the belly fin and with a slant stroke cut off this, the side fins, and the head, all in one piece. Then remove the back fin, and the spines beneath it, by making a deep incision on each side of the fin and pulling the latter out. The ventral part is removed in the same way. Open the fish, wash it in cold water, scrape off the slime, and then wipe it dry with a clean cloth or towel. Large fish, for broiling, should be split open along the back and the spine removed.
A special fish knife, with saw-tooth back for scaling, can be bought at a sporting-goods store. A good scaler is extemporized by nailing a common bottle cap on the flattened end of a stick.
A slippery, flabby fish is more easily handled for scaling if you sharpen one end of a stick as thick as your little finger and run it down through the fish's mouth about two-thirds the length of the body.
Fish taken from muddy or mossy water, or from cedar swamps, taste strong if cleaned in the ordinary way, unless special precautions are taken in cooking (see Chapter XVIII). The taint is not removed by scaling, for its cause is hidden deep in the roots of the scales. Such fish should be skinned. That is also the best way to prepare yellow perch.