Spread the spinach in a greased 13 x 9 baking dish. Place the fish on top.
Saute the onion in butter until tender. Stir in the soup, milk, swiss cheese,
cheddar cheese, curry powder, and pepper.
Cook over low heat, stirring until the cheese is melted. Spoon this over the fish.
Top with the cracker crumbs and parmesan cheese. Bake at 350 degrees for 30 minutes.