Wash and clean the zucchini and cut them into slices about 3 mm thick. Wash and clean the tomatoes and cut them into medium sized pieces. Peel and chop onion. Heat 1 tablespoon of oil in a pan and fry the zucchini in it. Add the onion and sauté briefly. Add the tomatoes and stew covered for about 10 minutes. In the meantime, wash the fish fillets, dab dry and season with salt and pepper.
Heat the remaining oil in a pan and fry the fish fillets in it for about 5 minutes on both sides. About 1 minute before the end of the cooking time, add the herb butter and lemon juice and sprinkle the fish with it. Season tomato-zucchini vegetables with salt and pepper. Arrange fish fillets and vegetables on plates, garnish with herbs and lemon wedges. Drizzle herb butter on the fish fillets. Serve with fresh bread