Combine first 6 ingredients in a small bowl, and stir well.
Rinse fillets, and pat dry with paper towels to remove excess moisture.
Sprinkle paprika mixture evenly on both sides of fillets; gently rub in seasonings.
Place a 12-inch cast iron skillet over high heat until hot.
Add 1 1/2 teaspoons butter, and tilt pan to coat bottom.
Add 2 fillets, and cook 2 minutes. Reduce heat to medium; turn and cook 4 minutes or until fish flakes easily when tested with a fork. Repeat procedure with remaining butter and fillets.