Fry the onion rings and garlic in a large saucepan in the hot olive oil together with the bay leaves, add the zucchini or fennel slices and fry with them. Deglaze with Noilly Prat, pour in white wine and cook briefly (3-4 minutes). Add the tomato cubes, season with salt, pepper, a pinch of sugar and nutmeg, add the fish stock and let simmer for 15 minutes.
In the meantime, chop the fish fillets into bite-sized pieces, season with salt and pepper and sprinkle with lemon juice. Add to the soup with the shrimp and let steep for another 5 minutes. Season the soup again to taste and serve sprinkled with dill and onion greens.
Fresh baguette and a dry white wine go well with this.