Combine first 9 ingredients, and stir well with a whisk. Pour yogurt mixture into a large zip-top plastic bag, and add fish to bag. Seal and marinate in refrigerator 20 minutes.
Prepare grill or broiler.
Remove fish from bag, reserving marinade. Place fish on a grill rack or broiler pan coated with cooking spray, and cook for 3 minutes on each side or until fish flakes easily when tested with a fork, basting frequently with reserved marinade.