Knowing when Fish is Done

Fish is usually done after about 9 minutes of cooking per inch [2.5 cm] of thickness at the thickest part, but any number of factors—a slow oven, fish that is very thick or thin, and whole fish versus steaks or fillets—can make the actual cooking time longer or shorter than you expect. The easiest method for determining doneness is to just stick a knife in the fish and look at the flesh. If it’s shiny and translucent, it’s still slightly undercooked. On the other hand, if the fish is flaking, it’s at least starting to overcook. The ideal appearance is just slightly translucent in the very center. With a little experience, you can judge the doneness of steaks and fillets by poking them with your forefinger in the same way you would meat. Fish that is cooked through will feel firm to the touch rather than fleshy. If you remove the fish from the heat as soon as it begins to feel firm, it will be the equivalent of medium, which is usually perfect for fish. Some fish, specifically fresh tuna, is often served rare, and salmon is best left a tad shiny and translucent in the middle. If you’re cooking whole fish, slide a small knife along one side of the back fin down to the backbone and peek under the flesh. If the flesh pulls away from the bone easily, the fish is done. If it looks translucent and clings to the bone, cook it longer. If you’re cooking very large whole fish, or don’t want to deal with the knife method, slide a meat thermometer into the back of the fish down to the backbone; the temperature should read 135°F[55°C].