Rinse fish, pat dry, sprinkle with lemon juice, and season with salt and pepper. Place flour in a shallow dish and dredge the fillets in it. Knock of excess flour.
Rinse and dry lettuce leaves and transfer to plates.
Sauté fish in a skillet in hot butter over medium heat for about 3–4 minutes on each side. Place fillets on the salad. Sprinkle with pomegranate seeds. Garnish with lemon slices to serve.