A change is sweeping the seafood industry: choosing frozen fish over fresh fish is now wiser. You can’t get much fresher fish than what is found in the freezer section because most of it is frozen as soon as it is caught. 85% of the seafood we consume is imported, and 70% of that fish has been frozen at some point. Even if you’re not a fan of frozen fish, chances are you’re eating it. And you’re probably relieved or even excited by this news if you’ve ever craved wild salmon in the dead of winter or don’t live close to a supplier of fresh seafood. The only drawback is clear: you must thaw the fish.
Although some types of fish, such as lean fish like tilapia and cod, can be cooked without even being thawed out (they can go straight from the freezer to the roasting or sauté pan), it’s usually best to fully thaw the fish before cooking. However, if you leave the fillets out on the counter for the entire day at room temperature, they become vulnerable to food-borne bacteria, which could lead to you passing out next to the fish. Sure, you can thaw fish gradually in the refrigerator. However, you wouldn’t still be reading this if you had the time to do that, would you?
No, you need a quick defrosting technique that won’t unintentionally partially cook some of the fish fillets (we’re looking at you, microwave). Instead, prepare a large bowl of hot water, put the frozen fish in a sealable plastic bag, and immerse the bag for five minutes in the hot water. Use a small bowl to weigh the fish down if it begins to bob up and down after being bagged.
Simply remove the fish from the water (see what we did there?) and determine whether it bends easily. If it does, youre all set to cook. If not, simply re-immerse it for one or two more minutes.
The fillets can be prepared for broiling, baking, or pan-searing once they have completely thawed out.
How to Defrost Fish
The main concern when defrosting frozen fish is food safety. That refers to preventing the development of bacteria that can lead to food poisoning. And it turns out that the safest method of defrosting fish is also the most effective.
Keep in mind that we’re assuming your fish is vacuum-sealed and commercially frozen. This includes single servings, such as steaks or fillets, as well as whole fish, like tilapia or trout.
Which of the two recommended methods you use to thaw frozen fish will largely depend on how much time you have.
Defrosting Fish in Cold Water
Defrosting your fish in cold water is the next best method and is much quicker. Again, assuming your fish is packaged to prevent moisture from getting to it, just put it in a shallow dish in the sink, fill it with water, and turn on the faucet just enough to let a thin stream of water flow into the dish. Additionally, make sure the water is cold—not warm or hot—at all times.
The fish will defrost more quickly in the cold water because it completely envelops it than in the refrigerator’s frigid air. Additionally, even a very small stream of water will have a slight convection effect, which will greatly accelerate the process. The time required for this technique shouldn’t exceed 30 minutes, but you can check it after 20 to see how it’s going. Once it has thawed, do the same as before: cut open the packaging, rinse the fish, and pat it dry with paper towels.
Additionally, you can combine the refrigerator method with the water method. Just submerge the package in water in a pan and place the entire thing in the refrigerator. This will take a little longer than the method using running water, but is still much faster than the method using a regular refrigerator. The benefit is that storing it in the refrigerator reduces the possibility of bacteria growing.
However, if the fish are not sealed in plastic, do not immerse them in water. This will cause it to become waterlogged. Before submerging, seal the item, if it isn’t already, in a plastic freezer bag with all the air squeezed out. To ensure that the fish is in contact with the cold water, it is essential to squeeze out the air.
Community Q&ASearch
Community Answer You have to let it thaw completely before preparing it for cooking. It is also not recommended that you freeze the cooked fish. Instead, cut the portion of raw fish you want to eat with a sharp knife before thawing it. 
Community Answer Flour the fish. Cook it on med-low heat in olive oil. 
Community Answer The egg mixture is best — you simply drain some of the egg mixture before putting them right in the batter, rather than drying them as youd have to with the water. FAQ
How long does mackerel take to defrost?
For both safety and flavor preservation, the fish must be kept in a sealed bag and immersed in water until defrosted. Leave until fully defrosted. Defrost time is typically six to eight hours per lb.
How do you defrost fish quickly?
No, you need a speedy defrosting technique that won’t unintentionally par-cook some of the thinner portions of the fish fillet (we’re looking at you, microwave). Instead, prepare a large bowl of hot water, put the frozen fish in a sealable plastic bag, and immerse the bag for five minutes in the hot water.
How do you defrost fish in 30 minutes?
Place the fish in a large bowl and defrost it in cold water. Fill the bowl with cold tap water. Submerge the fish in the cold water. Let it sit in water for about 30 minutes.
How do you defrost mackerel fillets?
Bluzette Carline of Seabest advises thawing frozen fish for 10 to 12 hours in the refrigerator before cooking. In a hurry? Thaw frozen seafood in cold water for 3–5 minutes.