Gently fry onion, garlic, chili, and celery; add wine and simmer briskly until reduced.
Add chopped tomatoes and anchovies.
Add fish stock and bring to a boil.
Add potatoes and simmer for 15 minutes.
Add prawns, cod, mussels, and coriander and cook for 5 minutes or until mussels are all open.
Season to taste; add lemon juice just before serving. If you prefer a hotter soup, add a splash of hot chili sauce.