Rinse fish; pat dry with paper towels. If necessary, cut fish into serving size pieces; set aside. In shallow dish combine flour and salt. Dip fish in flour mixture to coat.
In a large skillet heat half of the butter over medium-high heat. Add fish in a single layer. Reduce heat to medium. Cook 3 to 4 minutes per side or until golden and fish flakes easily when tested with a fork. Remove fish from skillet. Cover and keep warm.
Wipe out skillet. Add remaining butter to skillet and melt over medium heat. Stir in brown sugar until dissolved. Stir in pecans, sweet pepper and cayenne. Cook and stir over medium heat for 3 to 4 minutes or until pecans are lightly toasted and pepper strips are just tender. Remove from heat. Stir in lime juice. Spoon pecan mixture over fish. If desired, top with green onions.