Brown the bacon until crisp in a soup pot or large saucepan.
Drain off most of the fat, then add the onions and celery.
Sauté until the aromatic vegetables soften.
Add the milk, cream, wine, grated potato and bay leaves.
Stir and cook over medium heat until the potato has dissolved and thickened the soup, about 20 minutes.
Add the fish, season with salt and pepper and continue simmering just long enough to cook the fish through, about five minutes more.