Heat the oil in a large nonstick or cast iron skillet oven medium heat until it is shimmering. Add the fillets, skin side up, and cook until blackened, about 3 minutes. Flip the fillets and continue to cook until cooked through to your ,liking 5 to 7 minutes depending on the thickness of your fillets. If the skin is starting to burn before fillets are cooked, turn the heat down to medium low. If the fillets are extra thick (1 1/2 to 2 inches) in the middle) you may need to turn the fillets on their sides for a minute on each side to cook them through. An instant read thermometer inserted into the middle of the thickest fillet should read 120 to 130 for medium rare or 135-145 for more well done. Serve with lemon wedges.
