The best way to do this is to pack fish in ice or ice water that is 35 F or colder. Ice cools fish from the outside, and it can take considerable time for the center of a large fish to reach 32 F. Make an effort to store fish on ice as soon as possible for complete and rapid cooling. Table l gives the shelf life of lean fish at various storage temperatures. At summer temperatures above 80 F fish can lose most of its shelf life in a few hours. Cool your catch quickly to keep it from deteriorating to an unacceptable level of quality before it is refrigerated or frozen.
Ice Ice is the easiest and, usually, the least expensive way to cool fish.
As it absorbs heat from the fish or the environment, ice melts. In contact with the fish, melting ice cools it, washes bacteria from its surface, and keeps it from drying out. Crushed or flaked ice is best, because a greater amount of ice surface in contact with the fish ensures maximum cooling. Large pieces of ice can also crush, tear, or bruise fish more easily than smaller pieces. Large pieces of ice, however, are better than no ice at all.