Preheat oven to 450 degrees F. Coat a 9-inch baking dish with non-stick cooking spray. Rinse fish and pat dry. Arrange onion in the baking dish and top with fish fillets, skin-side down.
Mix olive oil, minced garlic and parsley together and spread over fish. Sprinkle with salt and pepper and a little paprika.
Bake, uncovered, 18 minutes until fish turns from translucent to opaque. Garnish with lemon wedges.