How To Tell If Fish Is Cooked – 8 Signs & The Cooking Temperature For Some Fish

How can you tell if your fish has transformed from raw to cooked before it becomes overcooked?

Most types of fish are tender and delicate, so it’s easy to go from perfectly cooked to overcooked in a matter of seconds. Moreover, people have different levels of doneness for their different fish dishes.

One common way people check for doneness is to poke the fish with a fork or slice it with a knife. While this isn’t so bad when cooking at home, it is disapproving if you are cooking for professional services. The rule of thumb says to cook fish to an internal temperature of 140-145°F (60-63°C).

There are ways to tell if fish is cooked and ready to be served and I’ll discuss them in this article.

How to tell if fish is cooked

1. Do the 10-minute rule

Another rule of thumb in cooking fish is the 10-minute rule. Measure the height of the thickest part of the fish and cook it for 10 minutes per inch of thickness, turning it halfway through the cooking time. The fish will need less cooking time if it is less than one inch thick.

This method works for broiling, grilling, baking, steaming, and frying. Begin to test for doneness at the minimum cooking time so you do not overcook your fish.

2. Check the cooking temperature

The recommended cooking temperature for fish is 140-145°F (60-63°C). However, just like with steak and chicken, people have different preferred levels of doneness. Also, different types of fish with their cooking temperature.

Know the internal temperature of the type of fish you are cooking or the cooking temperature of your desired level of doneness and follow it. Get a food thermometer, poke it into the thickest part of the fish, and read the temperature.

3. Do the knife test

You can also do the knife test to test for doneness. Insert a butter knife into the thickest part of the fish and keep the knife in place for three seconds. Be careful not to put the knife in too deep so you do not flake or cut the fish.

Remove the knife and place it on the tip of your bottom lip. If the knife feels warm, the fish is cooked. But if it is cold, it is still raw inside and needs more time to cook. It is safer to do this with a cake tester because it leaves a less visible mark.

4. Color change

There are visual clues that can help tell if your fish is cooked. Raw or undercooked fish have a translucent and shiny appearance. As it begins to cook and firm up, it turns opaque. However, the color change in fish varies with the type of fish you are cooking.

For instance, raw salmon is deep red. It turns light pink as it cooks. Cod goes from a glossy surface to a solidly white appearance as it cooks.

5. Crispy skin

Cooked fish have crispy skin. When you suspect that your fish is cooked, try to pick it up with a spatula. If it feels firm and crisped up, it is done and ready for eating. But if it feels loose and like it is falling apart, the fish needs more time to cook.

6. Flake the fish

Poke a fork into the thickest part of the fish and twist gently. If the fish is opaque and flakes apart easily without pushing and tugging, it is cooked and ready to eat. Undercooked fish feel tough, resist flaking, and look translucent.

Leave the fish to cook a little longer but keep an eye on it, especially if it’s a tender fish.

7. Loose flesh

This sign is usually used to tell if salmon fillets are cooked enough. When you suspect that your fish is almost cooked, press down the fillets with a fork.

If the flesh feels loose and separates along the white lines that run through it, it is done and ready to serve.

8. Secretion of albumin

Fish like salmon secret albumin, a white substance on their surface, as they near doneness. So, you cannot use this test to tell if cod or halibut is cooked. Once you see this appear on the surface of your fish, you can tell is cooked and ready to be eaten.

How long does it take to cook fish?

piece of cooked fish - millenora

Cooking time varies with the type of fish, cut, and thickness. Small and thin cuts will cook faster than large and thick cuts. Similarly, fillets will cook faster than whole fish.

Also, the cooking method you use determines how long fish cooks. Boiling and frying are faster than baking and roasting. The most important part of cooking is to check for its internal temperature and other signs that tell you your fish is cooked.

Different types of fish and their cooking temperature


The recommended cooking temperature for salmon is 125°F (52°C). It is best cooked to medium-rare when it is moist and begins to flake around the edges.

Salmon has a low collagen content and quickly loses moisture. If you do not keep an eye on the fish, it will become tough and unpalatable.

Lean white fish

Lean white fish are usually firm and tend to be meaty. Because of their firm texture, they can withstand more heat than salmon.

Cod, for instance, should be cooked to an internal temperature of 135°F (57°C). Halibut, on the other hand, is fleshier and more prone to moisture loss so it should be cooked to an internal temperature of 130°F (54°C).

If you have a food thermometer, poke it into the thickest part of the fish and read the temperature. If you do not have a food thermometer, check for visual clues like a change from a translucent to an opaque appearance with flaky edges.

Albacore tuna

If you are searing albacore tuna, cook it to 100°F (38°C). If you like your fish medium rare, cook it to 125°F (52°C). Also, check for visual clues like opaque skin.

Black cod

Black cod or sablefish is best cooked to an internal temperature of 140 to 150°F (60 to 65°C). It is high in omega-3 fatty acids and must be cooked to a point where it has a velvety appearance.

Common ways to cook fish


Steaming is a method of cooking fish without direct contact with the heat from boiling water. It is the best method for cooking fish like salmon, tilapia, cod, trout, etc. Fish can be steamed in a steam basket, en papilotte (in a paper bag/packet), or in a microwave.

The good thing about steaming fish is that it doesn’t add extra liquid to the fish since fish naturally comes with its water.


Baking involves cooking fish in an oven at a moderate temperature. This method is suitable for all types of fish. Moreover, it allows you to cook other items like vegetables alongside the fish.

Just like with baking chicken or turkey, you can enhance flavor and increase moisture by adding a liquid – chicken stock or white wine – to the pan as the fish bakes.

If you do not want extra moisture, simply coat the fish with flour, herbs, and breadcrumbs to make it crispy.


Grilling is a fast and convenient way of cooking fish using high and radiant heat. It is one of the best cooking methods to help preserve the skin of the fish. Grilling is most suitable for whole fish, skin on fillets, and fatty fish.

When grilling whole fish, make small cuts on the thickest parts of the fish to allow even cooking.

Before grilling, lightly rub both sides of the fish with oil, season it with oil and pepper, and stuff it with fruits and herbs to enhance the flavor of the fish. Flip the fish over in between grilling so both sides cook well.


Roasting and grilling are easily mistaken for each other, but they are different. Grilling refers to the method of cooking food over an open flame on a metal frame, whereas roasting is a method of cooking food slowly in an oven.

This method works best for fatty fish and fillets. It cooks fish without adding extra fats. As you do with chicken and turkey, stuff the fish with fruits, vegetables, and herbs to enhance the flavor.


Fried fish is one of the common forms of cooked fish. There are different ways of frying fish. You can shallow fry, deep-fry, stir-fry or cook it in an air fryer.

Fried fish is delicious, but frying is not very advisable because it loads foods with calories and can trigger the release of chemical compounds that can cause serious health issues.


Broiling also occurs in the oven but uses the broiler element to cook fish using direct and high heat. It seems a lot like grilling, but it doesn’t use a grill. Turn the fish halfway through cooking if it is thicker than an inch.


Pan-searing is the ideal method of cooking fillets. This method involves cooking fish at high temperature until it forms a brown crust. Before pan-searing fillets, make cuts on the fish to prevent it from curling up as it cooks.


Submerging fish in simmering liquid – broth, sauce, or milk – and cooking it on low heat allows the fish to absorb flavors as it becomes tender. It also allows the fish to cook evenly on all sides. The liquid you cook the fish in determines the resulting flavor of your fish.

Tips to keep in mind when cooking fish

  • Fish is delicate and cooks easily so do not be far from your cooking
  • When you need to continue cooking undercooked fish, check on it every minute to avoid ending up with overcooked fish
  • For even cooking, always cook fish on both sides
  • When cooking fish with the skin, start with cooking the fish with the skin down for crispy skin
  • Cooked fish easily break apart. Always pick them gently with a spatula
  • If you are cooking for guests or professional services, do not test for doneness by flaking with a fork. This makes it unpresentable. Use a cake tester instead


Is it safe to eat undercooked fish?

Eating undercooked fish exposes you to foodborne illnesses like salmonellosis and vibrio infections. Salmonella is found in raw or undercooked fish and can cause symptoms of food poisoning, such as diarrhea, abdominal cramps, and fever.

Eating undercooked fish is not advisable. Ensure you confirm the doneness of your fish before eating it.

Why did your fish turn mushy after cooking?

Fish becomes mushy after cooking if you have left it in an acidic sauce for too long or if it is overcooked. There is no way to fix mushy fish except you mash it and add it to another dish.

How do you know cooked fish has gone bad?

When cooked fish has gone bad, it develops a foul smell, a dry or slimy texture, and mold growth. Cooked fish begins to spoil when you store it too long or there has been an interruption in the power supply.

What is the best way to store cooked fish?

You can store cooked fish in the refrigerator or freezer, depending on how long you want to store it.

Cooked fish will last a few days in the fridge and months in the freezer. If you will be freezing, it will be better to freeze the fish in small portions, so you don’t have to thaw them all at once.


If you pay full attention to your fish, you will find it easy to tell that it is cooked and ready to be served. When cooking fish, invest your eyes, nose, and sense of touch to determine doneness. Yes, it can be that easy to tell.

With any of the pointers listed above, your next fish dish should come out perfect and presentable. You can now say goodbye to that overcooked rubbery texture that leaves you disappointed. So, get ready to cook your fish in all forms you can imagine.

After handling fish, use any of these effective ways to get the fish smell off your hands.

Thanks for reading.