Preheat oven to 350°. In a large skillet over medium heat, cook and stir celery and onion in 6 tablespoons butter until tender. Stir in bread cubes, pecans, orange juice, orange zest and 1/2 teaspoon salt. Transfer to a greased 13x9-in. baking dish. Arrange fillets over stuffing.
Melt remaining butter; drizzle over fillets. Sprinkle with remaining salt. Bake, uncovered, 25-28 minutes or until fish flakes easily with a fork.
In a small saucepan, combine sugar and cornstarch; whisk in water and orange juice until smooth. Bring to a boil, stirring constantly. Add cranberries; cook 5 minutes or until berries pop. Stir in orange zest. Serve with fish and stuffing.