Not-so-obvious sources of fish are widespread. These can include Caesar salad or a Caesar salad dressing, which typically contains some form of anchovy product, the Italian relish called caponata (also anchovies), patés, barbecue sauce, Worcestershire sauce, nearly any Asian sauce or dressing, and any form of imitation fish (as these use some proportion of genuine fish flavorings or ingredients). Fish oil is not supposed to contain fish protein, but it is safest to avoid in the case of severe allergies. Also avoid fish stock and fish soups. Read ingredient lists.
Watch out for accidental fish consumption in restaurants or in ordering take-out or delivery meals. Avoid seafood restaurants, even if you order a non-seafood dish, because of the risk of cross-contamination. Many ethnic restaurants, particularly those serving Asian cuisines, use fish and fish extracts. If you do prepare fish for yourself or another family member, protect the fish sensitive person from contact with the steam or smoke, as these can carry fish proteins.