Fish and Shellfish Allergy in Restaurants
Published 26 October 2026 · 6 min read
In the EU, fish, crustaceans and molluscs are three separate allergens. Fish include salmon, tuna and cod, crustaceans include prawns, crabs and lobsters, and molluscs include mussels, clams, squid and octopus. They also hide in dishes where you would not expect them: Worcestershire sauce, fish sauce, surimi, paella and Asian pastes. With a fish or crustacean allergy, it is therefore worth asking not only about the main ingredient but also about the sauces and the base of the dish.
Fish, crustaceans and molluscs are not the same thing
Under Regulation (EU) No 1169/2011, these are three separate items among the 14 allergens:
| Group | Examples | Number in the list of 14 |
|---|---|---|
| Fish | salmon, tuna, cod, sardines, anchovies | 4 |
| Crustaceans | prawns, crabs, lobsters, spiny lobsters, crayfish | 2 |
| Molluscs | mussels, oysters, octopus, squid, snails | 14 |
If you are allergic to fish, you do not necessarily react to crustaceans, and vice versa, as the proteins are different. Some people allergic to crustaceans do react to molluscs too, though, because their proteins are similar. An allergist will tell you which groups to avoid. You can read more about the difference between allergy and intolerance in Allergy, intolerance and coeliac disease, and see an overview of all the allergens in The 14 EU food allergens.
Where fish hides
- Worcestershire sauce traditionally contains anchovies.
- Caesar dressing is often made with anchovies.
- Fish sauce is the foundation of Thai, Vietnamese and Cambodian cooking.
- Surimi (imitation crab meat) is made from fish.
- Pizza with anchovies, and also some pizza and pasta sauces.
- Tapenade and some spreads may contain anchovies.
- Fumet (fish stock) and the stocks in soups and risottos.
- Sushi and rolls, including sauces, marinades and dashi (a Japanese stock made from fish flakes).
- Fish oil and omega-3 in supplements and some products.
Fish gelatine is also listed as an allergen in the EU. An exemption applies where it is used as a carrier for vitamins and carotenoids and as a fining agent in beer and wine. This is a detail for prepacked products, not for food in a restaurant.
Where crustaceans and molluscs hide
- Paella and seafood risotto: prawns, mussels and fish stock are the base.
- Curries and Asian pastes: shrimp paste (in Thai cooking, for example "kapi") is part of many curry pastes.
- Oyster sauce is made from molluscs and is commonly used in Asian wok dishes.
- Bouillabaisse, seafood soups, chowder.
- Prawn crackers are risky for people allergic to crustaceans.
- Sauces and dressings with seafood, such as XO sauce.
- Dumplings, rolls and vegetable dishes may have prawns in the filling.
Risky situations in a restaurant
| Situation | Why it is risky |
|---|---|
| Asian wok dishes | fish and oyster sauce, shrimp paste |
| Sushi bar | shared knives, boards and rice |
| Spanish and Mediterranean cuisine | paella, seafood soups, fish stocks |
| Grilling and frying | a shared grill or oil for fish and other dishes |
| Italian cuisine | anchovies in sauces and on pizza, seafood in pasta |
| Dressings | Caesar dressing, fish sauces |
With seafood, also be careful about cooking: steam or vapour from cooking molluscs and crustaceans can in some cases cause a reaction. For people with a very sensitive allergy, it is therefore sometimes advised to avoid venues that specialise in seafood altogether. Always discuss this with your doctor.
What to ask
- Does the dish contain fish, crustaceans or molluscs, including in the sauce, stock or paste?
- Is there anchovy, fish sauce, shrimp paste or oyster sauce in the sauce?
- Are fish and other dishes fried in the same oil?
- Do you use the same board and knives for fish and other dishes?
- Is "imitation crab meat" (surimi) part of the dish?
For tips on asking so that the staff understand you, see How to ask about allergens in a restaurant. If you are asking in a foreign language, see How to explain your allergy in another language. The numbers on a menu (usually fish 4, crustaceans 2, molluscs 14, but check the legend) are explained in Allergen numbers on menus.
Fish allergy on holiday
On a seaside holiday, seafood is eaten everywhere and is routinely prepared in large shared kitchens. Before you travel, find out how to say that you are allergic to fish or crustaceans, and take the medication your doctor has recommended. In hotels and buffets, the risk of contamination from shared cutlery is higher. The article on holidays with coeliac disease, Coeliac disease on holiday, contains tips that can also be used for other allergies.
Cross-contamination
Even a dish with no fish or seafood in the recipe can come into contact with it on a shared grill, in shared oil or on shared knives. What warnings such as "may contain traces" mean is explained in May contain traces.
In AvoiDino you can set fish, crustaceans or molluscs as your allergens and filter dishes. The data is for guidance only, so always check with the staff.
Frequently asked questions
Is Worcestershire sauce fish-free?
Traditional Worcestershire sauce contains anchovies, so it contains fish. Vegetarian versions exist, but in a restaurant ask which product they use.
Are fish, crustaceans and molluscs one allergy?
No. In the EU they are three separate allergens. Some people react to only one group and others to several, which an allergist will assess.
Does surimi contain fish?
Yes. Surimi is made from fish and only imitates crab meat. It may also contain other allergens, such as eggs or wheat.
Is oyster sauce a fish sauce?
Oyster sauce is made from oysters, so from molluscs, not fish. If you are allergic to molluscs, avoid it and ask about it in Asian dishes.
Can I eat at a sushi bar if I am allergic to fish?
It is risky. Fish is prepared there on shared boards and with the same knives. If you are considering a sushi bar, agree it with the kitchen in advance and discuss it with your doctor.
Sources
- Regulation (EU) No 1169/2011 of the European Parliament and of the Council on the provision of food information to consumers, Annex II (list of substances causing allergies or intolerances) and Article 44 (non-prepacked food).
This information is general and does not replace medical advice. If you have an allergy, always check the ingredients with the staff.