Frozen fish should be thawed gradually to avoid health risks. Do not thaw frozen fish at room temperature or run under hot water as the outside will thaw faster than the inside, and encourage the growth of dangerous bacteria.
Thaw frozen fish and seafood gradually by placing it in the refrigerator overnight.
Seal frozen fish and seafood in a plastic bag. Seal the bag and immerse it in cold water, then put a small slit in the bag and microwave it on the “Defrost” setting. Stop the microwave when the fish is still icy but pliable, so that the fish is thawing but not beginning to cook.