Preheat oven to 350 degrees F (175 degrees C). Lightly coat an 8x8 baking dish with cooking spray.
Rinse cod filets and pat dry. Place fish in a single layer in the baking dish. Mix together milk, onion, lemon pepper, parsley and salt; pour over fish filets. Drizzle filets with lemon juice.
Bake in preheated oven for 15 minutes, or until fish is firm and can be flaked with a fork.
