How to Clean a Frozen Fish

Odor: Should have little or no odor. Do not buy if they have a strong fish odor.

Skin: Should be solidly frozen and have no discolorizations.

Wrappings: Moisture-proof with no air spaces between fish and wrapping.

The best seafood is the freshest seafood you can get, no more than two or three days out of the water.

Don't buy frozen seafood if its package is open, torn or crushed on the edges.
Avoid packages that are positioned above the "frost line" or top of the freezer case in the store's freezer.
If the package cover is transparent, look for signs of frost or ice crystals. These could mean the fish has been stored a long time or thawed and refrozen - in which case, choose another package.

When you're preparing fresh or thawed seafood, it's important to prevent bacteria from the raw seafood from spreading to ready-to-eat food.

Wash hands thoroughly with soap and warm water before and after handling any raw food.
Wash the cutting board with soap and hot water to remove food particles and juices after using it for raw foods such as seafood, and before using the board for cooked or ready-to-eat foods or preparing another food item.
As an added precaution, sanitize cutting boards by rinsing them in a solution made of one teaspoon of chlorine bleach in one quart of water - or run the plastic board through the wash cycle in your automatic dishwasher. Or, consider using one cutting board only for raw foods and another only for ready-to-eat foods such as bread, fresh fruit and vegetables, and cooked fish.
As a rule of thumb, avoid using cutting boards that are made of soft, porous materials. Instead, choose those made of hard maple or plastic, and make sure they are free of cracks and crevices. Smooth surfaces can be cleaned more easily and thoroughly.

BellyBytes.com