Today, frozen fish does not necessarily mean less fresh or lower-quality fish. In fact, many large fishing boats have facilities so that fishermen can freeze the fresh catch immediately on the boat. But with almost all foods that are frozen, you must first thaw fish before cooking it. With the proper method, you can thaw fish quickly and safely to ensure quality and prevent the development of bacteria because of improper thawing.
Remove the piece of fish from its packaging. This might be a plastic box, wax-lined paper, plastic back or wrap.
Cover the fish with a clean piece of cling film. Make sure that the cling film is airtight. You don't want any water penetrating the cling film and reaching the fish while you are thawing it.
Fill a large bowl with water that is colder than room temperature.
Place the fish into the bowl and submerge it into the water. It might sink on its own, but if not, then weigh the fish down with a weight, such as a pie weight.
Wait for the fish to feel pliable, but still cold to the touch. You don't want it to be too soft and mushy, which means that it has over-thawed and has started to come to room temperature. That could mean that it is no longer safe for consumption. Therefore, depending on the size of the fish, check it every five minutes to see if it is starting to become pliable. Once pliable, you can cook it.
While thawing it in a bowl is the fastest and safest way to thaw a frozen fish, to be extra safe, thaw the fish overnight in your refrigerator.