Some of the freshest fish is not fresh but frozen. Fish deteriorates rapidly, so many fishing companies have begun flash-freezing their fish while it's still on the boat. Even fish sold in stores as "fresh" is typically actually freshly thawed frozen fish. To bake frozen fish, you have three options: Thaw it and then bake it; thaw it in the broiler and then bake it; or thaw in in the oven as it is baking.
Choosing Frozen Seafood
If the fish thaws during transport, the quality will deteriorate rapidly. Watch for a few warning signs when choosing frozen fish. Avoid fish whose packaging has been damaged. Avoid fish that has been sitting above the frost line in the freezer case at your store. Fish stored too high in the case may have thawed slightly and then refrozen one or more times. Avoid fish with ice crystals inside the bag. Crystals signal thawing and refreezing or simply old fish.
Probably the best, certainly the most common, way to bake frozen fish is to thaw it first. The safest way to thaw fish is to put it in the refrigerator for a day. Place it in a sealed container to keep thawed juices from dripping into other food. If you are pressed for time, you can thaw fish in water. Seal the fish in a freezer bag and submerge it in cold water in the refrigerator. This method will thaw the fish at a rate of one or two hours per pound. Don't thaw fish at room temperature. Doing so allows any pathogens in the fish to flourish; these can cause food-borne illness when you eat the fish. Once the fish is thawed so it has no ice crystals inside the flesh, you can bake it using any recipe calling for fresh fish.
If you are pressed for time, you can thaw fish under the broiler. Some fish is frozen with an ice glaze. An ice glaze is a thin coating of ice on the fish. If your fish has an ice glaze, thaw it by running the fish under cold water. Dry the fish with a paper towel. Place the fish on a broiling rack. Brush it with a little oil and broil it 4 to 5 inches from the heating element for five minutes. Flip it, brush it with a little more oil, and broil it for another two to three minutes. Transfer the fish to a baking dish and bake it at 400 degrees F until the fish flakes when tested with a fork, the "San Diego Union-Tribune" instructs. If you want to add any sauce, vegetables or wine, do so after broiling but before baking.
It is also possible to put frozen fish directly into the oven to bake. Set your oven to 450 degrees F. Remove any ice glaze and pat the fish dry. Brush the fish with an oil that can take the 450-degree heat. Soy, canola or peanut oil will work fine. Place the fish into a baking dish and bake it for four minutes to thaw. At this point you can add butter, spices or any other seasoning you desire. Bake for an additional eight to 12 minutes or until the fish flakes when tested with a fork.