How to Identify Bad Fish

Eating bad fish can cause food poisoning, so it's important to take extreme precaution when assessing the freshness of your fish

Fish is one of the primary foods, thanks to its high nutritional value and easy digestibility. There are many ways to conserve and transport fish with the goal of keeping it fresher for longer. However, sometimes these methods don’t work out. Therefore, you have to know how to identify bad fish.

Actually, distinguishing between fresh and spoiled fish is more complicated than you’d think thanks to “modernity.”

This phenomenon is due to the fact that most people want convenience when buying fish, so they want them filleted and decapitated. It’s easier to eat these fish without knowing if they’re fresh or not, because you normally buy them already frozen.

Fish in Bad Shape

Identify Bad Fish

  • Smell: Fish in poor condition usually have a bad odor that smells rancid, and occasionally smell like ammonia.
  • Skin: Fish in poor condition have very soft skin that easily detaches from its scales and meat.
  • Eyes: Fish in poor condition have sunken eyes, creamy corneas, and gray pupils, as if they had cataracts.
  • Gills: Their gills are behind their head, and in fish in poor condition, they’re yellowed or gray.
  • Guts: This is the first affected zone from aging; fish in poor condition will be swollen or flaccid and sunken.

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Fish in Good Shape

Fish in Good Shape

Smell: Fresh fish smells like seaweed, the sea, and conserves all of their nutrients.

Skin: On the contrary to what was mentioned above, fresh fish has a vibrant color, with hard and shining scales.


Eyes: Fresh fish has protruding eyes, with black pupils that glisten.

Gills: Fish gills when they’re fresh will be pink or red, depending on the species, clean, bright, and without mucous.

Guts: The meat is firm and not slippery.

Tips to Prevent Unwanted Surprises With Your Fish

Tips to Prevent Unwanted Surprises With Your Fish

So that you don’t have to throw it away, we recommend that you cook your fish within a few days of buying it from the supermarket.

If this isn’t possible, you can freeze your fish. This guarantees its that it will stay fresh for longer. By freezing it, it conserves its properties and prevents the risk of food poisoning.

  • Eating fish that have been in the freezer if you have not been home for a few weeks can be quite risky.
  • This is due to the fact that you don’t know if there were power failures, which would mean that the fish was not properly frozen.

Generally speaking, frozen products shouldn’t be out of the freezer for longer than 2 days after they have been frozen.

On the other hand, freezing them again is never recommended. If you discover defrosted fish due to power failure, the safest option is to throw it away.

Refrigeration and freezing prevent the proliferation of more bacteria, but it doesn’t kill them.

This allows the decomposing process to accelerate. Therefore, if your freezer or refrigerator has stopped working for any reason, it’s better to throw out the fish.

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The Moisture Content

The Moisture Content

To cook a fish, you should look at whatever the fish is sitting in to see if it has a lot of frozen liquid or if it’s dry.

When the liquid is present in the bag or container, this means that there could have been some kind of power failure that caused the fish to defrost.

If freezing the fish is ideal, even if the wrapping is dry, you still need to make sure that the fish is fresh.

Defrost it, look at it and smell it. If it has the normal smell and appearance, it’s safe to eat. If not, it’s probably not a good idea.

Fish shouldn’t be eaten the same day it’s caught it salt water. Dry it well and first put it in the refrigerator.

Finally, you’ll know if it’s fresh or not once you take that first bite.

Here you can evaluate its flavor: if it doesn’t taste sour or acidic. Your taste buds will know if something doesn’t taste right.

If all is in order, you can eat it!

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