Preheat the oven to 350 degrees. Mix ¼ cup of the olive oil, the tomato, onion, lemon juice, parsley, dill weed, salt and pepper in a bowl. Cut 4 medium pieces of heavy-duty foil and drizzle 1 tablespoon of the remaining olive oil over each piece.
Arrange 1 filet in the center of each piece of foil and top each with ¼ of the tomato mixture. Bring the edges of the foil over the fillets and seal tightly. Arrange the packets on a baking sheet and bake for 20 minutes or until the fillets flake easily when tested with a fork.