Some home cooks are comfortable gauging the doneness of their wild-caught seafood by checking to see if it flakes easily with a fork. Despite being a low-tech way to determine how tender and flaky your fish is, this is actually a highly reliable method to determine when to pull seafood from the heat when you know what to look for.
However, there are going to be times when you prefer to use a kitchen thermometer to get an accurate read on the doneness of your fish. Using an objective measurement to determine doneness is something that can help you if you’re new to cooking fish. If you’re an old hand when it comes to wild-caught seafood, using a thermometer will allow you to gauge doneness without having to pull apart your fish. To get the best results by using this method to determine doneness, you’ll want to use an instant-read digital thermometer, inserting the probe into the thickest part of your fish to measure its internal temperature.
The optimal internal temperature of wild-caught seafood is unique to each variety of fish, depending on factors like fat content and protein structure. Keep in mind that “optimal,” ultimately, should reflect your personal preference in texture and doneness. But we’ve got some general rules of thumb with fish temperature to get you closer to perfection.
Why the USDA Recommends 145 Degrees
If you’re pregnant or need to consume a low-microbial diet for any other reason, the optimal internal temperature of all seafood, including shellfish, is 145 degrees at its thickest part, full stop. That’s the magic number that indicates that any microbes living in your seafood will be obliterated by the heat so that your risk of food-borne illness is significantly reduced.
Anytime you cook fish to a temperature below 145 degrees or consume it raw — a similar rule applies to meat, poultry, eggs, and shellfish as well — it opens you up to the risk of contracting a food-borne illness.
One thing that you won’t ever have to worry about regardless of the internal temperature of fish, though, is the presence of a parasite called anisakid, which are nematodes resembling worms that are naturally found in wild-caught fish. These nematodes are part of a healthy ecosystem, hitching a ride in plankton, fish, and large sea mammals, but they cause an allergic reaction in humans. Like other seafood purveyors, we take a few precautions that ensure that these are removed or rendered harmless; actually, simply the act of freezing the fish for a short period of time completely eliminates any health risk that these nematodes present to us.
Why You’d Want to Go Lower
Cooking wild-caught varieties of seafood to 145 degrees may prevent you from getting food poisoning, but you won’t be left with a fillet of fish that flakes easily with a fork.
When you cook lean fillets to that temperature, registered at their thickest parts — the thinner parts of the fish are going to reach an even higher internal temperature — the fillet likely will be tough and hard to flake, despite what certain culinary blogs suggest.
To best appreciate the texture of cooked, wild-caught fish, you’ll want to go lower.
There’s an unofficial consensus among foodie blogs that sockeye or coho should be cooked to 120 degrees to achieve medium rare doneness. This is when a fillet of salmon is at its peak flakiness, with a tender, jewel-toned center. Cooking it beyond this temperature, you raise the possibility that your fillet of wild salmon will be overcooked.
Cod and Halibut
Lean fillets of wild-caught fish like cod, halibut, and rockfish can handle higher internal temperatures, and actually won’t reach peak flakiness at 120 degrees. When cooking cod, rockfish, or halibut, you’ll want to aim for an internal temperature anywhere between 130 and 135 degrees, depending on your personal preference. The fillets will be firm, flake easily with a fork, and nearly opaque in their centers. Beyond this temperature, things can get tough and dry — especially for halibut — so err on the cooler side until you have the doneness dialed in.
Being a fattier fish, sablefish, can also handle temperatures that are closer to USDA recommendations. This fat content makes it incredibly forgiving, despite the fact that you’ll often be broiling it or grilling it over high heat. When cooking sablefish, you’ll want the center of the fillet to register at 135 degrees.
Wild Alaska Pollock
With our pollock Quick Cuts, because of their size, it’s unrealistic to measure the temperature of each piece. Rather than going by the internal temperature of pollock to determine doneness, it’s going to be easier for you to just peek into the center of a piece of fish to see if it’s nearly opaque. If you do want a concrete temperature to go by though, 135 degrees is good.
A Final Word
Again, these temperatures are suggestions that will leave you with fillets that are tender, neither underdone or overcooked. If you like something a little more or less cooked, you can go a little higher or lower than these recommendations.
One thing that may factor into how accurately these temperatures are at getting you a perfectly cooked fillet is how much of an impact carryover cooking will have on your fish. Carryover cooking is basically the cooking that happens after you pull your fish from the heat, since the fish still retains some of the residual heat from your cooking surface even after it’s on a plate. The hotter your cooking surface, the more carryover cooking will have an effect on the internal temperature of your fish after it has rested for several minutes.
For example, pulling a fillet of salmon from a hot grill at 120 degrees can leave you with a fillet that registers at closer to 130 degrees by the time that carryover heat dissipates. If you find that carryover cooking is leaving you with fish that are more cooked than you’d like, pull the fish from the heat when it’s a few degrees cooler than our optimal recommendations, especially when you’re working with hot cooking surfaces.
Consuming raw or undercooked meats, poultry, seafood, shellfish, or eggs may increase your risk of foodborne illness, especially if you have a certain medical condition. The FDA recommends an internal temperature of 145°F for cooked fish.