Mix together onions, celery, mushrooms, thyme, rosemary, tarragon and butter. Spread half of mixture in a greased baking dish and add the scaled and cleaned fish. Sprinkle with Parmesan cheese, top with remaining vegetable mixture. Bake 35-45 minutes a t 375 degrees F or until tender and flaky, basting 3-4 times with melted butter or chicken broth. Use 1 tsp herb type if fresh chopped.