How to tell when fish is done

Use our chart to get it right every time.

Recipes often tell us to cook fish “until it flakes easily with a fork” or “until just opaque.” These may be relatively useful doneness tests, but neither one tells us enough. To cook fish fillets and steaks perfectly—whether poaching, broiling, baking, grilling or pan-frying—the secret is in the thickness of the fish. Our chart explains.

Thin fillets are not more than ½-inch thick. These include sole, haddock, snapper, catfish and flounder.

Thick fillets average about 1 ½ inches thick. Cod, center-cut salmon and halibut, monkfish, roughy and grouper are typically thick fillets.

Steaks are almost always cut at least 1-inch thick and include species such as swordfish, tuna, mahi mahi and salmon.

It takes practice to be able to judge the thickness of fish with a single glance. Until you become a whiz at it, just use a ruler—we do!

TIPS:

• Always check doneness of fish at its minimum cooking time. Be sure to stop cooking when the fish is just short of done—fish will continue to cook for a minute or two when removed from the heat.

• When fish “flakes with a fork,” it is usually a bit overcooked and may be dry. This test is better: Using your finger, press on the cooked flesh gently. When it is done, the fibers will separate in solid flakes. If the fibers fall apart, the fish has been cooked too long.

• The Department of Agriculture recommends that all fish be cooked until an instant-read thermometer inserted into the center reads 145°F.

Some people enjoy fatty fish, such as salmon and tuna, served medium rare. If you intend to prepare fish cooked to medium rare, be sure that the fish you select has been previously frozen—freezing eliminates any parasites that may be present. Pregnant women, small children, the elderly and people with compromised immune systems should be particularly careful when consuming.