When you are grilling fish on your gas grill, 10 minutes at LOW per inch of thickness is a great rule of thumb. When the fish flakes easily with a fork, it is done.

SOME FISH HANDLING AND COOKING TIPS:
  1. Fish should be brushed with melted butter or oil before placed on the grill. Brush well with more butter or oil several times while it is cooking. Turn once.
  2. Avoid over handling fish during grilling. Cooked fish is delicate and will flake easily. Turn once.
  3. With smaller fish or filets, a grid or wire basket makes turning your fish on the grill easier. Coat your grid or basket with a non-stick spray for easier handling.
  4. To grill frozen fish, partially defrost it before cooking it as you normally would.
  5. Another way to grill fish is in foil packets. Add lemon juice, white wine, or smoked paprika for more flavor.