Guest recipe by Judith Fertig an Karen Adler
Authors of Fish & Shellfish, Grilled & Smoked: 300 Foolproof Recipes for Everything from Amberjack to Whitefish, Plus Really Good Rubs, Marvelous Marinades, Sassy Sauces, and Sumptuous Sides
Watch her interview on The Woman's Connection YouTube Vlog

1. Select only the freshest fish and shellfish. Fresh fish has a glistening, dewy look, a sweet or briny smell of the sea, and a somewhat firm texture. Shellfish has a sweet or briny smell of the sea, too. Ask to smell the fish or shellfish before you buy. Even the slightest odor of ammonia means the fish is not the freshest. You can also judge freshness by texture-if you
press the center part of a fillet or steak with your finger and the impression stays, the fish is not fresh. If you're buying a whole fish, look at the eyes-if clear and bright, the fish is fresh; if opaque or cloudy, the fish is not fresh. If you buy flash-frozen fish or shellfish, make sure it
still frozen when you buy it. You'll have the best luck if you buy your fish from a reputable and knowledgeable fishmonger-he or she can help you select the best options.

2. Handle fish and shellfish carefully. Always keep fish and shellfish chilled before grilling. Rinse thoroughly under cold running water, then pat dry. Discard any oysters, clams, or mussels with cracked or open shells.

3. Marinate fish and shellfish for only 30 to 60 minutes in the refrigerator before grilling. Marinating longer could mean an overpowering flavor of the marinade instead of the delicate flavor of fish. The vinegar or citrus juice in the marinade could also "cook" the fish and you'll end up with ceviche. However, there are some types of firmer-textured or oily, full-flavored fish
and shellfish-such as bluefish, mackerel, marlin, monkfish, octopus, shark, tuna, or squid-that can take a longer marinade.

4. For grilling, it is preferable to leave the fish skin on. Always place a fillet flesh side down first, then turn halfway through grilling onto the skin side. This technique helps the fish fillet hold together better during grilling.

5. Grill just about any fish or shellfish you like. Very thin and delicate fish such as Dover sole or lake perch are better sauteed or broiled. Catfish fillets are great on the grill because they hold together well and taste great.

6. Grill over a hot fire. Hold your hand 5 inches above the heat source. If you can only leave your hand there for 2 seconds, your fire is hot.

7. The general rule for grilling fish is 10 minutes per inch of thickness. For a fillet or steak that is 1 inch in the thickest part, you grill flesh side down for 5 minutes, then turn and finish grilling for 5 minutes on the skin side. For shellfish, grill for about 2 to 3 minutes on each side or until the shellfish becomes more opaque and firm in texture.

8. Test for doneness by making sure the fish and shellfish are opaque and somewhat firm. Most fish are done when steaks or fillets begin to flake-not a dry flake, but more a moist separation and you see a clear liquid-when tested with a fork in the thickest part. For firmer-fleshed varieties such as farm-raised catfish, monkfish, sturgeon, walleye pike, or eel, the fish flesh should be all one color, when tested in the thickest part, and the texture
firm. If you prefer your salmon or tuna on the medium-rare side, look for opaque pink or grayish brown on the outside, glistening reddish pink or dark purple-red on the inside, just as you would judge the doneness a beef steak. Shellfish are done when they turn more opaque and firm up in texture. Underdone fish or shellfish can always be put back on the grill or zapped in the microwave for a few seconds. Overcooked fish or shellfish can't be rescued.

9. Grill gadgets that rule: two long-handled wide metal spatulas for fish steaks or fillets and long-handled tongs for shellfish. For delicate fish like flounder or skate wings and very small shellfish like clams or baby squid, use a perforated grill rack, disposable aluminum pans, Nordic ware fish boat, or aluminum foil as a base so that the fish won't fall through the
grill grates. Although your fish or shellfish won't have grill marks, it will still have the flavor of the grill-and be a lot easier to remove. Perforated grill woks allow you to stir-grill marinated fish and vegetables together. 

10. Because you never know what fish or shellfish will be the freshest when you shop, be ready to substitute. You'll want to match the same firm, moderate, or delicate texture and mild, moderate, or full flavor of the fish or shellfish you originally planned on. For example, if cod is unavailable or not very fresh, substitute U.S. farm-raised hake, hoki, whiting, or
turbot-similar matches in delicate texture and mild flavor. In place of moderate-textured and mild-flavored red snapper, try catfish, grouper, haddock, orange roughy, walleye, or whitefish. In place of firm-textured, mild-flavored shrimp, substitute lobster, prawns, soft shell crab, or even halibut or monk fish.