Michigan State University Extension
Preserving Food Safely - 01600803
Water is the most effective airtight package. Three good ways to seal fish in water are glazing, ice blocks without prior freezing and ice blocks with prior freezing.
Glazing- This method works especially well for whole fish, but other portions can also be frozen this way. Freeze fish in a protective plastic bag. Prepare a pan of very cold, almost frozen water. Remove frozen fish from plastic bag, dip in the very cold water and return to freezer. Repeat dipping and freezing until the ice glaze is 1/8 to 1/4 inch thick. Fish can be stored without further wrapping, but the ice glaze will gradually evaporate. To improve keeping quality, wrap glazed fish in freezer wrap, date and store.
Ice Block 1- Place a single layer of fish in shallow pan, such as a cake pan. Cover with water and freeze solid. Remove block from pan, wrap in freezer wrap, date the package and return to freezer.
Ice Block 2- This method creates the least amount of pressure on tender fish flesh. Place a single layer of fish in a shallow container. Place pan in freezer overnight to freeze fish solidly. The next morning, cover the frozen fish with water and freeze. Remove frozen block from pan, wrap, date and store.