Wash whole fish, steaks, or fillets under cold running water if necessary before wrapping them for the freezer. It is also important to keep oxygen in the air away from the fish to prevent rancidity caused by oxidation. To avoid these quality changes, wrap fish or fillets well. The best wrapping material prevents oxygen penetration and water vapor loss. Plastic wraps, aluminum foils, freezer wraps, or wax cartons can be used.
Plastic wraps are best because they fit more tightly and exclude more air.
A good way to freeze fish is to wrap it in cling wrap and then put it into a plastic bag, removing as much air as possible. This method is especially useful if the fish is to be stored in a frost-free freezer, which can remove considerable moisture in a short time. Freezing fish in meal-size individual packages reduces handling, speeds up freezing time, and makes defrosting easier. Glazing also inhibits oxidation and dehydration. To glaze a fish, dip it into cool water and then put it into the freezer.