Choosing fresh fish guide

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What to look for when buying fresh fish

This page is reproduced by kind permission of the Seafish Industry Authority

Fish can be sold whole or cut into fillets, steaks or cutlets. Most fishmongers and supermarkets will skin, clean, bone and fillet any fish for customers. It is convenient to classify fish as white, oil-rich or shellfish.

White fish are also called demersal fish. They live on, or near the sea-bed and may be round or flat. Round fish live near the sea- bed, e.g. cod, coley. Flat fish live on the sea bed, e.g. plaice.

Oil-rich fish are also called pelagic fish. They swim near the surface of the sea and are found in shoals, e.g. herring, mackerel.

Shellfish such as Lobster and Crabs, are all invertebrates (i.e. do not possess an internal skeleton) and are split into two main groups: molluscs have either an external hinged double shell (e.g. scallops, mussels) or a single spiral shell (e.g. winkles, whelks), or have soft bodies with an internal shell (e.g. squid, octopus); crustaceans have tough outer shells which act like armour, and also have flexible joints which allow quick movement (e.g. crab, lobster).

This checklist summarises the main points to look for when choosing fish.






Once fish has been selected, it has to be handled and stored carefully. Spoilage is mainly caused by the actions of enzymes and bacteria.

Enzymes are present in the gut of the living fish and help convert its food to tissue and energy. When the fish dies, these enzymes carry on working and help the bacteria in the digestive system to penetrate the belly wall and start breaking down the flesh itself.

Bacteria exist on the skin and in the fish intestine. While the fish is alive, the normal defence mechanisms of the body prevent the bacteria from invading the flesh. Once the fish dies, the bacteria invade the flesh and start to break it down, the higher the temperature the faster the deterioration. (Note these bacteria are harmless to humans)

Fish, once caught, has a shelf life of I0 to 12 days if kept properly on ice. (Comment:- but at their best in the first 5 days. Jeff)


In a refrigerator the storage temperature should be between 0°C and 5°C.





White fish

I -2 days

3 months

Oil-rich fish

1 -2 days

up to 2 months

Smoked fish

2-3 days

up to 3 months


I -2 days

I month

Cooked fish

I -2 days

2 months