Thoroughly wash the hornfish, cutting them into fourths. Pat dry and drizzle with the juice of one lemon.
Spread out flour on a large plate. Dredge each fish piece in flour, tapping off excess flour. Flavor the fish with salt and pepper to taste.
Heat up butter, until it starts bubbling, in a large skillet. Cook the fish, giving each side only about 2 ½ minutes to prevent the fish from drying out.