The temperature of the freezer should be 0 F or lower. When freezing large amounts of food, scatter the packages throughout the freezer so the food freezes quickly. Thaw fillets in the refrigerator, in the microwave or under cold running water. Food defrosted in the microwave should be cooked immediately. Other thawed fish should be used within one to two days.
Thorough cooking destroys harmful bacteria and parasites.
The United States Department of Agriculture recommends using a meat thermometer and checking to make sure that fish is cooked to an internal temperature of 145 F. A good rule of thumb to follow is to cook fish 10 minutes for every inch of thickness. Small, thin fillets will cook in just a few minutes. Fish is done when the flesh has just begun to turn from translucent to opaque or white and is firm but still moist. Overcooked fish is tough and dry. Once fish is cooked, keep it hot or chill it.