Preheat the oven to 450 F. Spray a baking dish large enough to hold the fish in a single layer with nonstick spray.
In a small bowl, combine the breadcrumbs with the melted butter, Parmesan (if using), garlic powder, salt, and pepper.
Place the fish filets in the prepared baking pan, skin-side down, if applicable. Sprinkle the breadcrumb topping evenly over the fish. Bake for about 15 minutes, until the fish flakes easily with a fork and the topping is golden brown and crunchy. The internal temperature should be 145 F on an instant-read thermometer.
Serve with the lemon wedges and a sprinkle of parsley.
Notes
Begin checking the fish for doneness after about 8 minutes of cooking time per inch. You can do this by inserting a very thin, sharp knife into the thickest part; if it slides in with barely any resistance, the fish is cooked through. When you tilt the knife, you should see that the flesh of the fish is opaque throughout or possibly has just a hint of translucence in the middle.The internal temperature should be 145 degrees when measured with an instant-read thermometer. The fish will continue cooking for a few minutes after it is removed from the heat.