Step #1 Melt 2 tbsps of the butter In a large-ish skillet.
Step #2 Spice up the catfish fillets with salt & pepper & the cayenne.
Step #3 Coat the catfish fillets lightly with flour, then add them to the skillet & cook over moderately high heat, turning once, until golden brown on both sides & cooked though, about 10 mins.
Step #4 Transfer the catfish fillets to a platter; tent with foil wrap & keep warm.
Step #5 Melt the remaining 4 tbsps of butter in the skillet.
Step #6 Add the pecans & cook over moderately high heat, until the pecans & butter are browned & fragrant, about 3 mins.
Step #7 Stir in the lemon zest & juice & season this with salt.
Step #8 Spoon the pecan butter over the catfish fillets & serve as soon as possible with lemon wedges.