If you don't like fish with a strong fishy odor or taste, select milder varieties such as tilapia, halibut, flounder, Arctic char and catfish and stay away from bluefish, salmon and other distinctly flavored species. Freshness and proper handling post-catch are important, so buy from reputable sellers and choose fish with a mild odor, shiny -- not slimy -- flesh and meat that springs back into place when pressed. Still, all fish deteriorate over time, which increases the fishy flavor, but you can often eliminate or mask it.
What's That Smell?
While alive, most fish and other types of seafood produce a naturally occurring compound called trimethylamine oxide. After death, though, the compound begins breaking down into trimethylamine. This byproduct is what's most responsible for the infamous fishy odor and flavor. The older the fish, the more of this stinky compound it contains. It doesn't mean that the fish is bad, but it can definitely detract from the cooking experience and the quality and enjoyment of the meal.
Give It a Milk Bath
Milk is the simplest way to counteract a strong fishy odor and taste in a less-than-super-fresh piece of fish. The casein protein in milk binds to the trimethylamine, facilitating removal. Pour enough milk into a dish to fully submerge the fish. Place the fish in the milk and let it soak for 20 minutes, then remove the fish and blot it dry with paper towels. You remove much of the trimethylamine along with the milk.
Spice It Up
While a quick milk marinade addresses the underlying cause of a strong fishy smell and taste, another option is to mask it with spicy or other potent seasonings. Coat a fillet in Cajun or blackening seasoning or use a healthy dose of curry powder. An Asian-influenced approach with soy sauce or tamari and a liberal amount of ginger also helps. A bold herb mix, such as herbs de Provence or Italian or Tuscan seasonings is another option.
Other Preparation Options
If you don't soak the fish in milk, a strong-flavored acidic marinade comprising a bold red wine, vinegar, lemon juice or lime juice can cover up a fishy taste. Thin fillets only need to stay in the marinade about 10 minutes, while thicker fillets and steaks can go up to 20 minutes; don't soak fish longer or it can develop a mushy texture. Cooking the fish on the grill imparts a smoky flavor that helps mask a fishy flavor, while baking, broiling and pan-searing tend to highlight the food's own flavor. If you plan to bake it, use a cedar or another wood plank to introduce a masking flavor. Another approach is to use fishy-tasting fish in a dish with other strong components, such as a stew, paella, gumbo or curry.