How To Tell If Fish Has Gone Bad (Smell, Touch, Taste)

With any food item, it is important to prepare and handle fish safely before you cook it in order to reduce the risk of food-borne illnesses, and ensure you have a delicious meal.

And when it comes to fish, things can get tricky…Do you know how to tell if fish has gone bad?

Whether its fish you’ve just caught, fish you purchased, or old fish in the back of the freezer…i’ll tell you the easy tell tale signs to be sure you’re eating good and tasty fish.

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How To Tell If Fish Has Gone Bad?

The easiest and most obvious way to tell if your fish has gone bad is by giving it the ‘smell test‘. Fish that is not safe to eat will have a strong chemical or rancid smell, similar to ammonia.

If you are unable to smell the fish, the next way to tell if your fish has gone bad is by the touch. Does the fillet feel slimy? Does it have an outer mucus coating? These are bad signs of spoiled or turned fish.

Fish fillets or fresh fish should feel wet, but if properly cleaned and prepared it should not have a slime or mucus coating.

How To Tell If Fish Has Gone Bad (Smell, Touch, Taste)

Immediately after fish are caught and killed, bacteria begin to break down compounds on the surface of their skin which then gives off that strong fishy odor. This odor intensifies as the fish begins to spoil.

Note: Just because a fish smells ‘fishy’ does not mean it’s bad to eat. Some species of fish have a higher oil content, dark meat, and diet that make them smell fishier than others.

The key is to keep an eye out for rancid, sour, chemical or rotting smells.

Here are the Tell Tale Signs Your Fish Has Gone Bad

  • You notice a “fishier” smell than normal or a sour, rancid, or ammonia-like smell.
  • There are signs of drying around the edges of the fillet, discoloration, dark spots, or freezer burn.
  • Fillets are dull or grayish in color or translucent and mushy.
  • The exterior of the fish has become wetter and there is a noticeable slimy film that has formed on the outside of the fillet.
  • Your fillet is mushy.
  • If you are purchasing whole fish and their eyes are white, creamy, or gray and their gills are yellow or gray, or their skin is shiny.
  • If you are purchasing frozen fish and the meat is bendable.
  • Fish not properly stored in temperatures of 40 degrees Fahrenheit or colder before preparation.

If the flesh of the fish is not shiny and the skin is still firm, the fish is likely still edible. If it is mushy, slimy, or gray in color- beware!

Can You Cook Fish If It Smells?

There is a difference between pungency and inedibility.

All fish lovers know fish has a natural odor. However, if your fish is giving off a foul odor, or the meat is mushy, slimy, gray, or translucent in color, it likely is spoiled and you should not proceed with cooking.

Whole tilapia for sale

Pro tip: If you want to remove some of the fishiness smell/flavor from any of your fillets, try soaking your fish in milk for about 20 minutes. The casein in milk binds to compounds on the outside of the fish’s flesh and removes the odor.

How To Tell If Cooked Fish Is Bad

Many people confuse a fishy taste with inedibility. But that is not the case. Fish can smell and taste fishy, and be perfectly edible.

To tell if cooked fish is bad, give it a smell the smell test. Do you smell a strong chemical odor that turns your nose sour? Is the cooked fillet mushy and inconsistent (soft, hard, chewy etc)? These are signs your cooked fish is not good to eat.

This may seem obvious, but if you purchased ready-cooked fish from your local market, check the “use by” and “expiration dates” on the packaging.

Measure the temperature of your fish. Most seafood should be cooked to an internal temperature of 145°F. Undercooking could result in illness.

Cooked fish should smell mild, not sour. The flesh should always be firm and never mushy. The flesh should be white or slightly pink in color and separate easily with a fork.

Does Cooking Spoiled Fish Make It Safe?

Although cooking raw fish can kill off bacteria that are currently present, it can’t rescue fish that has already gone bad. 

Eating spoiled fish, even though it has been cooked, can cause both Ciguerta and Scombroid poisoning.

Scombroid poisoning occurs when people eat fish that was stored improperly.

Scombroid is not discernible by taste or smell. So if you are eating a fish and it has a peppery taste, or the skin looks like a honeycomb, Don’t eat it.

In the case of scombroid poisoning, the appearance and taste of the fish appear normal, and neither cooking nor freezing the fish can prevent it.

Can You Taste If Cooked Fish Is Bad?

Just ask anyone who’s eaten bad fish, or rotten fish…its usually an experience they wont forget.

Fresh Salmon fillets

Most of the time, your senses will kick in and you will smell bad fish before you have the misfortune of actually eating it. Cooking spoiled fish will only make the bad smells worse. Nobody wants that!

If you smell ammonia, notice mushy slimy meat, it has gone bad and you should discard it immediately.

What Happens If You Eat Fish That Has Gone Bad?

In most cases, if you eat bad fish it’s just an unpleasant experience. You spit it out, and grab the nearest glass of water to wash out your mouth.

If you eat old, spoiled, or undercooked fish you run the risk of contracting two types of food-borne illnesses including Ciguerta and Scombroid.

Symptoms are likely to occur rapidly and typically occur within one hour of eating the spoiled fish.

Symptoms of Ciguerta Fish Poisoning include itching, tingling, and numbness of the lips, tongue, hands, and/or feet.

Symptoms of Scrombroid Poisoning are headache, dizziness, sweating, and burning of the mouth and throat. Symptoms begin within 10 to 90 minutes after eating the implicated fish.

How To Tell If Fish Is Bad Frozen?

If you are purchasing whole fish, from a local store or market, their eyes should be clear and shiny not white and cloudy. Their flesh should be firm, with red bloodlines, and the gills should be healthy and red.

Ask the clerk or seafood dealer when the fish was caught to determine if it is fresh. If your in an area where there is a commercial fishing presence, you should be able to find out when, and even where it was caught!

Assorted frozen fish for sale

Inspect the fish to see if a slimy coating or smell is present.

Fish can dry out when stored in the freezer, so look to see if the meat has turned grey or brown, has formed colored patches, or has developed freezer burn. If any of these are present they are indications the meat has gone bad.

Check for a temperature indicator on the packaging to ensure the product has been stored at the proper temperature.

How Long Does Fish Last In The Fridge?

Raw fish should only be kept in the fridge for 1-2 days before cooking.

Fish should be stored in a moisture-proof container, at or below 40 degrees Fahrenheit, or bacteria can begin to develop. The colder the refrigerator, the better!

Cleaned fish (fillets only) can last up to 2 days in the refrigerator, as long as they are in a dry container and the fridge is very cold. But I strongly recommend eating your thawed or fresh fish as soon as possible…if not, pack it up and freeze it for later use!

How Long Does Fish Last In The Freezer?

Depending on the fat content and type of fish, raw frozen fish can be kept in the freezer up to a year, if properly stored and packed (such as vacuum sealed).

The leaner the fish the longer it tends to keep in the freezer.

However, there are reports of people keeping and eating fish from the freezer that are 2, 3, even 4 years old!

In any case, after thawing out your frozen fish you’ll want to inspect the fillets and give it the smell test and other signs we discussed.

Frozen fish fillets

Pro Tip: Always label your fish fillets with a permanent marker. Write the date the fish was caught, and the type of fish. Chances are your not going to remember 6 or 9 months down later.

How Long Is Thawed Fish Good For?

Thawed fish is good for up to 2 days, as long as it’s stored at a cold temperature (like in the refrigerator).

Frozen fish should be thawed gradually in the refrigerator overnight and fish should be kept chilled until it is ready to serve.

NOTE: Avoid thawing fish in the microwave…as this will actually cook the outer edges of the fish and keep the center still frozen, which makes it less appetizing.

When preparing fish do not leave it out of the refrigerator for more than 2 hours as bacteria can develop.

Final Thoughts

There is nothing worse than getting a whiff of rotten fish, or that strong sour-seafood taste after your first bite…yuck!

Take time to properly prepare your fish, and always confirm it’s freshness by giving it the smell test, and checking for other signs of spoilage:

  • Sour, pungent odor.
  • Slime or mucus coating.
  • White gills, cloudy eyes,
  • Gray, mushy meat texture.

I hope the tips in this article prevent you from ever eating fish that has gone bad…and instead you enjoy delicious fresh fish that is healthy and fun to catch!

Thanks for reading.

Growing up in Florida, I’ve been surrounded by saltwater my entire life…and I love sharing my passion with others.

To learn more about why I started Saltwater Mecca, visit the ABOUT page.

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