In experimenting with this dish, I found that the fish would fall apart in the simmering liquid during cooking, so I sauté it ahead. Go easy on the spice: Cioppino is a delicate soup with the taste of seafood and tomato shining through rather than a spicy gumbo-like stew. I always keep a jar of dry roux (light, not dark) to use sparingly in soups, stews, and gravies to add flavor and to thicken.