Stir together first 7 ingredients in a saucepan over medium-low heat; cook, stirring occasionally, 10 minutes.
Sprinkle fish with pepper; arrange in an even layer in a lightly greased aluminum foil-lined broiler pan. Pour barbecue sauce over catfish.
Bake at 400° for 10 to 12 minutes or until fish flakes with a fork. Garnish, if desired.