A fillet bought for tonight’s curry can quickly become tomorrow’s food-safety question. How long does fish keep depends on whether it is fresh, cooked, frozen, smoked or thawed, and on how promptly it has been chilled. Fish is highly perishable, so a little planning when unpacking the grocery delivery helps protect both flavour and safety.
How long does fresh fish keep in the fridge?
Fresh fish and seafood should usually be cooked within one to two days of purchase or delivery when stored in a fridge at 5°C or below. This applies to fish fillets, whole fish, steaks, prawns, squid, mussels and similar chilled seafood.
For the best result, use very fresh fish on the day it arrives. White fish such as cod, haddock, sea bass and sea bream is at its most delicate when cooked promptly, while oily fish such as salmon, mackerel and sardines can develop stronger flavours sooner. Shellfish deserves particular care: live mussels and clams should be cooked as quickly as possible, ideally on the day of purchase.
Always follow a product’s use-by date where it is sooner than the general one-to-two-day guidance. A use-by date is a safety date, not a suggestion. Do not eat chilled fish after this date, even if it appears acceptable or has no obvious smell.
Keep fish in its sealed packaging until needed, unless the packaging is damaged or likely to leak. Place it on a plate or tray on the bottom shelf of the fridge, where juices cannot drip onto ready-to-eat food, fruit or vegetables. If you have bought fish from a counter or it is loosely wrapped, transfer it to a clean covered container. Keeping it very cold matters more than adding extra seasoning or marinade.
How long does cooked fish keep?
Cooked fish keeps for one to two days in the fridge. This includes baked salmon, fried fish, fish pie, grilled sea bass, prawn curries and leftover seafood pasta.
Cool cooked dishes promptly before refrigerating them. As a practical rule, get leftovers into shallow covered containers and chill them within two hours of cooking. Large portions take longer to cool, so divide them rather than leaving a full casserole dish on the worktop. Once chilled, use leftovers for a next-day lunch or supper rather than saving them for later in the week.
Reheat cooked fish until it is piping hot throughout, and only reheat it once. Cold cooked fish can be suitable for salads or sandwiches if it has been chilled safely and remains within its use-by and storage time.
How long does fish keep in the freezer?
Freezing is the simplest option when plans change. Fresh fish can be frozen before its use-by date and is best used within three months for good texture and flavour. It remains safe for longer if continuously frozen at -18°C or below, but quality gradually declines. Delicate fillets may become dry, and fatty fish can pick up freezer flavours more readily.
Freeze fish in portions that suit the way your household cooks. Wrap it tightly or use a freezer-safe airtight container, removing as much air as possible. Label each pack with the contents and freezing date. This is particularly useful if your freezer includes a wide range of fish, prawns, dumplings, ready meals and frozen vegetables.
Cooked fish can also be frozen, preferably within a day of cooking. Use it within one to two months for the best eating quality. Creamy fish pies and sauces can freeze well, though the sauce may separate slightly after thawing. Stir gently while reheating and check that the dish is hot throughout.
Do not refreeze raw fish that has fully thawed unless you cook it first. If it was thawed in the fridge and is still very cold, cooking it and then freezing the cooked dish is the safer route.
Thaw fish safely
The safest way to thaw frozen fish is in the fridge. Place the sealed pack on a plate or tray and allow enough time for it to defrost slowly, often overnight for fillets and longer for a whole fish or a large pack. Once thawed, cook it within 24 hours.
If time is short, many small fillets and prawns can be cooked from frozen. Check the pack instructions and allow extra cooking time. This can work especially well for frozen white fish portions, peeled prawns for a stir-fry, or seafood added to a curry or soup near the end of cooking.
Avoid thawing fish on the kitchen worktop. The outside can warm into the temperature range where bacteria multiply while the middle remains frozen. Defrosting in the microwave is also best reserved for fish that will be cooked immediately afterwards, as some areas may begin to cook during defrosting.
Storage times for smoked, cured and packaged fish
Not every fish product follows the same timetable. Vacuum-packed smoked salmon, hot-smoked mackerel, gravadlax, marinated anchovies and cured fish should be kept refrigerated and used by the date on the packet. Once opened, they commonly need using within one or two days, but the label takes priority.
Tinned fish is different. Unopened tins of tuna, sardines, mackerel or anchovies are shelf-stable until their best-before date when stored in a cool, dry cupboard. After opening, transfer any unused fish from the tin to a covered container, refrigerate it and use it within two days. Do not store leftovers in an opened tin.
Fish in a chilled ready-to-eat meal, sushi or a seafood sandwich should be treated as highly perishable. Keep it cold, follow the use-by date and eat it on the day it is opened. Sushi containing raw fish should not be kept for a later meal.
Check freshness before cooking
Dates and cold storage come first, but sensory checks can help you spot fish that should not be used. Fresh whole fish should have clear, bright eyes, red or pink gills and firm flesh that springs back when pressed. Fillets should look moist and glossy, not dull, sticky or dried around the edges.
A mild sea or clean-water smell is normal. A sharp sour, ammonia-like or strongly fishy smell is not. Discolouration, sliminess or a swollen packet are also reasons to discard the product. With shellfish, throw away any live mussels or clams that remain open when tapped before cooking, and discard any that do not open during cooking.
Do not rely on cooking to make spoiled fish safe. Heat can kill many bacteria, but it cannot reliably remove toxins that may already have formed, nor restore quality.
A practical routine for fish deliveries
When a grocery order arrives, unpack chilled fish before pantry items. Check that it feels cold, review the use-by date and decide whether it is for a meal within the next day or two. Refrigerate what you will cook soon and freeze the rest straight away.
For family meals, it helps to assign each pack a purpose: salmon for a traybake, white fish for fish fingers or curry, prawns for noodles, and a frozen portion for a busy evening. This approach reduces waste without limiting the variety of seafood on the menu.
Keep raw fish separate from cooked foods, wash hands and preparation surfaces after handling it, and use separate utensils where practical. If you are marinating fish, do so in the fridge, not at room temperature. Dispose of any marinade that has touched raw fish unless it is boiled thoroughly as part of the recipe.
Fresh fish rewards simple, timely handling. Put it away cold, cook it while it is at its best, and freeze portions early when your plans may change. That leaves you with safer meals, better texture and more freedom to enjoy the seafood you have chosen.