Freezing fish is a subject that confuses some people so they shy away from it. But if you stick to a few simple rules then it's nearly as simple as freezing meat.
Fresh fish from a market is just as suitable for freezing as fish caught by yourself.
If you are planning a fishing trip and want to freeze your catch then click here for details on how to handle the fish after catching and then how to clean it up. At that point, return to this page to see how it's prepared for the freezer.
The basic rule is that you only freeze fish which will be cooked after it has thawed. Do not use fish that has been frozen for sushi.
SELECTING FISH FOR FREEZING
When buying fresh fish, first smell it. It should smell fishy but not have other odd smell. Don't buy a fish if it smells of ammonia.
If the fishmonger will allow you to touch the fish (unlikely for hygiene reasons) then run your finger over the skin. It should be smooth, and have a clear slime covering. Reject fish that have lumps or bumps on the skin. The flesh should have an elastic feel to it which returns to normal shape after you press it.
If the fish is whole (click here for how to clean and gut a whole fish), examine the skin as described above. The eyes should appear clean and bright not dull and glazed.
If you are buying fillets of fish the flesh should be moist. It should also be free from damage and bruising.
GENERAL PREPARATION FOR FREEZING
If you have a whole fish then you will need to de-scale it if the fishmonger hasn't done this for you. Use the back of a knife to remove the hard scaly parts of the skin. Start at the tail and drag the knife along the surface towards the head. Don't underestimate the messiness of this task nor the time it takes if you are not experienced!
If at all possible get your fishmonger to do the job. Failing that, place the fish in a large plastic bag and de-scale it in their. This will reduce the number of scales which will inevitably spin off all round your kitchen
Plan how you intend to eat the fish and the amount required for a meal's worth. Cut the prepared fish into portions as if it was about to be cooked.
Lean fish (click here for a list of oily and lean fish) which is cut into portions should be dipped in salted water (50g salt to 1 litre water / 2oz to 2 pints) for 20 seconds. Oily fish which is cut into portions should be dipped in an ascorbic acid solution (2 teaspoons ascorbic acid to 1 litre / 2 pints of water).
Take a meal sized amount of fish, separate the portions with freezer paper or kitchen foil, cover them tightly twice with kitchen foil then place in a marked freezer bag. Exclude as much air as possible from the plastic bag. If you have a fast-freeze facility in your freezer turn it on a couple of hours before and use it for freezing fish.
When preparing portions of fish, think carefully about how it will be thawed. Small portions of fish will thaw much quicker than large portions resulting in better quality fish. Click here to go to our page on thawing.
SPECIFIC FISH AND CUTS
De-scale the fish (see general preparation above) then clean and gut it (click here for details).
Wrap the fish in kitchen foil twice excluding as much air as possible. Place the fish in a marked and sealed freezer bag then freeze.
Fillets of Fish
Click here for our page on how to prepare a fillet of fish for freezing.
Crab must be cooked before freezing. The classic way to cook a crab is to put it live into a pot of boiling salted water. Make sure the pot is at least 10cm (4in) wider than the largest crab because it's claws will grab the side of a pan that is not wide enough. Been there, done that!
Possibly more humanely, they can be anesthetised by putting them on ice for 15 minutes and then cooking them.
Cook for roughly 15 minutes per 450g (1lb) in boiling salted water. Cool the cooked crabs under running cold water and drain them. Remove the edible flesh from the body (brown) and claws (white). Place the flesh in a freezer bag (excluding air and sealed) or a freezer container (allow 1cm / ½in of space at the top for expansion). Crab meat will keep for about 4 months in the freezer.
Crab frozen in this manner will need to be cooked for 10 minutes after thawing.
Proceed as for crab but allow 4cm / 1½in of space for expansion.
Only freeze live oysters. If you have the space, oysters can be frozen in their shells. However normally only the flesh is frozen. Clean the shells by washing under running water. Remove the shells keeping the liquid from inside the shell. Wash the flesh in lightly salted water.
Place the flesh and the saved liquid either in a labeled freezer bag or freezer container. Allow 1cm / ½in of space at the top for expansion during the freezing.
Prawns and Shrimps
Cook prawns in boiling salted water for 5 minutes, 4 minutes for shrimps and smaller prawns. Leave them in the water until they cooled sufficiently to handle them. Remove the shells and place them in either in a labelled freezer bag or freezer container. Allow 4cm / 1½in of space at the top for expansion during the freezing. If they are still warm then chill them in the refrigerator for half an hour before freezing.