Pulse toasted bread slices into bread crumbs using food processor; should yield about ½ cup breadcrumbs.
Preheat oven to 375 F. Grease a medium baking sheet.
Stir together milk and salt in a shallow bowl.
Combine bread crumbs, paprika, and Parmesan cheese in another shallow bowl.
Pat fish fillets dry with a paper towel.
Coat fillets by dipping first into milk mixture, then into crumb mixture.
Arrange breaded fillets on the prepared baking dish, leaving space between. Drizzle melted butter over fillets.
Bake fish for 25 to 30 minutes, depending on the thickness of fillets. The fish should flake easily with a fork when done.
Serve immediately, with a lemon wedge and tartar sauce for dipping.
Recipe adapted from: www.thespruceeats.com