Fish Internal Temperature Guide: Why 63°C Is the Standard

Fish is the most delicate protein most people cook. It goes from perfectly done to overcooked in under a minute. The texture changes from tender and flaky to dry and rubbery without much warning. And unlike beef, there's no "medium-rare fish" for most species — the USDA recommends a fully cooked temperature of 63°C (145°F) for almost all fish.

Fish Temperature Chart

The key difference in this chart: tuna. Unlike salmon, cod, and tilapia, tuna is often served medium-rare (52°C / 125°F) when cooked as a steak. The reason is texture — tuna becomes dry and fibrous when fully cooked. Medium-rare is standard at restaurants, and many home cooks prefer it the same way.

Why 63°C / 145°F Is the USDA Standard

The USDA's 63°C (145°F) recommendation for fish is based on parasite destruction. Many fish carry parasites (roundworms, tapeworms) that are killed at this temperature. For raw fish applications (sushi, poke), the fish is either previously frozen to kill parasites or sourced from suppliers who guarantee parasite-free products. For cooked fish, the temperature is the safety standard.

Salmon: The Most Popular Fish

Salmon is the default fish purchase in most North American and European households. It's fatty, forgiving, and works with almost any cooking method. Target temperature is 63°C (145°F), at which point the fish is opaque throughout and flakes easily with a fork.

The texture window: Salmon stays moist up to about 66°C (150°F). Past that, it dries out fast. For a restaurant-quality result, pull at 60°C (140°F) and let carryover finish the cook during a 2-3 minute rest.

Probe placement: Insert from the top into the thickest part of the fillet. For skin-on salmon, insert just above the skin, not through it. The skin is insulating and gives a false low reading.

Tilapia and Cod: Lean White Fish

These are lean fish with very little fat. They cook faster than salmon and dry out more aggressively. The same 63°C (145°F) target applies, but the margin for error is smaller. Overcook tilapia by 5°F and it becomes chalky.

Visual check: Both fish turn fully opaque white when done. If there's any translucency, it's undercooked. For fillets under 1 inch thick, an instant-read thermometer is faster and more reliable than visual guessing.

Tuna: The Exception

Tuna steak is the only common fish where medium-rare is standard. Target is 52°C (125°F) for a pink center with a seared exterior. At 63°C (145°F), tuna is fully cooked but often dry and fibrous — not the texture most people want.

The sushi-grade distinction: If a customer is cooking tuna to medium-rare, they should confirm it's sushi-grade or previously frozen per FDA parasite destruction guidelines. This is especially important for vulnerable populations (pregnant women, elderly, immunocompromised).

Shrimp and Scallops: Fast-Cook Seafood

Both shrimp and scallops target 63°C (145°F), but they cook extremely fast — 2-3 minutes total. The visual cues are more reliable here than temperature: shrimp turn pink/orange and curl slightly; scallops turn opaque throughout and feel firm.

Why a thermometer still matters: For large shrimp (U10 or U12 count), or jumbo sea scallops, the internal temperature is a useful cross-check. Smaller shrimp and bay scallops are almost always cooked visually.

Why Fish Overcooks So Fast

Fish muscle is more delicate than beef, pork, or chicken. The connective tissue breaks down at lower temperatures, and the proteins coagulate faster. A salmon fillet reaches done temperature in half the time of a chicken breast of similar thickness.

This is why instant-read speed matters. A thermometer that takes 10 seconds to read means 10 seconds of continued cooking while the pan is still hot. For fish, those 10 seconds matter. Lonnmeter instant-read thermometers deliver readings in 3-5 seconds — fast enough to check and pull without overshooting.

What Thermometer Features Matter for Fish?

Common Fish Temperature Mistakes

• Overcooking "just to be safe" — 63°C is safe. Going to 70°C doesn't make it safer, just drier.
• Not checking the thickest part — Thin fillets cook unevenly. Check the center of the thickest section for an accurate read.
• Leaving the probe in too long — Fish is delicate. A probe left in a hot pan continues to conduct heat into the fish, creating overcooked spots around the insertion point.
• Assuming all fish cook the same — Tuna is different from salmon. Scallops are different from cod. Teach the species-specific guidance.

For Distributors and Retailers

Fish is a category where customers often lack confidence. They know fish is healthy, but they're uncertain how to cook it without drying it out. Providing a temperature reference — either printed with the thermometer or available as a downloadable guide — addresses that uncertainty directly.

For seafood retailers bundling thermometers with fish sales, this guide works as a POS handout. "Cook to 63°C / 145°F" is the single most useful instruction you can give a fish buyer.