Preheat oven to 425°F. Combine corn, undrained tomatoes, onion, 1/2 teaspoon dill and 1/4 teaspoon salt in medium bowl.
Place four 18x12-inch pieces of heavy foil on counter. Place about 3/4 cup corn mixture in center on each piece of foil.
Sprinkle remaining 1/2 teaspoon dill, remaining 1/2 teaspoon salt and pepper over fillets. Place 1 fillet on corn mixture for each packet. Double fold top and ends of each piece of foil, leaving space for steam to gather.
Place packets on baking sheet; bake 20 minutes or until fish flakes easily with fork (145°F). Carefully open ends of packets to allow steam to escape before fully opening. Serve immediately.