How to Tell If Fish Has Gone Bad (MUST KNOW!)

If you consume fish gone bad, it can cause food poisoning. A good way to find out if a fish has gone bad is to smell it. If it has a rancid smell or smells like ammonia, it’s a sign of spoilage.

What is the best way to tell if fish has gone bad?

First things first: check the way it smells. If its fishy odor is sour or spoiled, throw the fish away.

When buying fish, look at its eyes. If the corneas are creamy, the eyes are sunken and the pupils are grey, do not buy.

You should also look at the gills behind the head. If they are yellow or gray, look for fresher fish. The skin should also be soft and easy to detach from the meat and scales. If the meat is mushy, it’s not a good sign.

The guts are also important since it’s the first area that will be affected if the fish has gone bad. If it’s flaccid and swollen, it’s a telltale sign the fish has gone bad.

Fish gone bad
Fish gone bad

How do you know if fish is safe to eat?

The freshest fish should have an ocean smell. The skin will have firm, shiny scales and a vibrant color.

The protruding eyes will have black pupils that glisten and the gills will be red or pink, depending on the type of fish. It will also have no mucus.

When you look inside, the meat should be firm and not slippery.

Fresh fish
Fresh fish

How to Tell if Fish Has Gone Bad

There are several things you can do to tell if the fish has gone bad:

When you remove the fish from the refrigerator, feel it to see if it has a slimy coating. As it ages and goes bad, the outer surface will get wetter until it eventually develops a thin layer of slimness. This is a clear sign your fish has started to spoil. As soon as you notice the slimy texture, discard the fish.

If the fish has been cooked, it will not get slimy when it starts to go bad. However, you should check the smell and this goes for both cooked and raw fish. If the refrigerated fish has started to go bad, its fishy smell will be more pungent. As soon as it starts to smell bad, get rid of it.

When it comes to raw fish, you should also check the color. The meat should be a white or light pink color, but if it has white lines, discoloration and a milky glossy coat (sometimes with a blue or grayish tint), it is going bad.

When you take fish out of the freezer, make sure to look for signs of freezer burn, especially if it has been there for over 9 months.

Look to see if any crystallized ice peaks are forming on the fish’s surface, along with any discolored patches. If you notice any, it is best to discard the fish.

How do you store fish?

How to delay fish going bad? Check these practical tips:

  • Store cooked or raw fish in an airtight container before you put it in the fridge.
  • If you know you will not eat the fish within 5 or 6 days of purchasing it, cooking it, or before it expires, you can also freeze it. 
  • To freeze fish, put it in an airtight plastic bag or wrap it tightly using plastic wrap.

How long does fish last?

  • If you have been keeping fresh fish in the refrigerator or forgot it was in there, check the sell-by date on the fish before you decide to cook it. If it is 2 days (or more) past the sell-by date, throw it away.
  • The package may have a use-by date (expiration date) instead of a sell-by date; if it does, the same principle applies.
  • Remember to keep cooked fish in your refrigerator for a maximum of 5 or 6 days past the sell-by date.
  • Frozen fish can be kept for 6 to 9 months. It does not matter if it is cooked or raw. (The only exception to this rule is smoked salmon that only lasts 3-4 months.)
  • Most will discard the original packaging, so make sure that you write down the shelf life on the container you used to store the fish.

The Takeaway

You can tell if fish has gone bad not only by its smell but also by its appearance and by touching it. Always check your fresh or frozen fish before consuming it to avoid the danger of getting food poisoning.

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