Place fillets in a single layer in a well-greased 13- x 9- x 2-inch baking dish. Melt 2 tablespoons butter; pour butter and lemon juice over fillets, and sprinkle with 1 teaspoon salt. Broil 4 inches from heating element 10 minutes or until fish flakes easily when tested with a fork. (Do not turn.)
Cook bacon in a heavy skillet until crisp; drain bacon pieces, reserving drippings in skillet. Add remaining butter to bacon drippings. Sauté green onion and garlic in drippings until tender. Add mushrooms and flour, stirring until smooth. Cook over low heat 1 minute, stirring constantly. Gradually add catsup, wine, water, and remaining salt; cook over medium heat, stirring constantly, until slightly thickened and bubbly.
Place broiled fillets on a serving platter. Spoon sauce over fillets; sprinkle with reserved bacon. Serve immediately.