Place the fish in a buttered baking dish. Preheat oven to 350 degrees. Mix together the tomatoes, parsley, garlic, tarragon, olive oil and salt and pepper. Stir in the Parmesan cheese. Carefully spoon over each fillet. Bake for 20 minutes or until the cheese is melted and the fish flakes easily. Spoon any pan juices over the fish, serve.