Fish Allergy

Finned fish can cause severe and potentially life-threatening allergic reactions (such as anaphylaxis). Allergic reactions can be unpredictable, and even very small amounts of fish can cause one.

If you have a fish allergy, keep an epinephrine delivery device with you at all times. Epinephrine is the first-line treatment for anaphylaxis.

To prevent a reaction, it is very important to avoid all fish and fish products. Always read food labels and ask questions about ingredients before eating a food that you have not prepared yourself.

Steer clear of seafood restaurants, where there is a high risk of food cross-contact. You should also avoid touching fish and going to fish markets. Being in any area where fish are being cooked can put you at risk, as fish protein could be in the steam.

More than half of people who are allergic to one type of fish are also allergic to other fish. Your allergist will usually recommend you avoid all fish. If you are allergic to a specific type of fish but want to eat other fish, talk to your doctor about further allergy testing and recommendations.

Finned fish is one of the eight major allergens that must be listed in plain language on packaged foods sold in the U.S., as required by federal law, either within the ingredient list or in a separate “Contains” statement on the package. This makes it easy to see if finned fish is present in a food item. 

There are more than 20,000 species of fish. Although this is not a complete list, allergic reactions have been commonly reported to:

• Anchovies
• Bass
• Catfish
• Cod
• Flounder
• Grouper
• Haddock
• Hake
• Halibut
• Herring
• Mahi mahi
• Perch
• Pike
• Pollock
• Salmon
• Scrod
• Sole
• Snapper
• Swordfish
• Tilapia
• Trout
• Tuna

Also avoid these fish products:

• Fish Flavoring
• Fish gelatin, made from the skin and bones of fish
• Fish oil
• Fish sticks (some people make the mistake of thinking these don’t contain real fish)

Some Unexpected Sources of Fish

• Barbecue sauce
• Bouillabaisse
• Caesar salad and Caesar dressing
• Caponata, a Sicilian eggplant relish
• Imitation or artificial fish or shellfish (e.g., surimi, also known as “sea legs” or “sea sticks”)
• Worcestershire sauce
• Certain multicultural cuisines (especially African, Chinese, Indonesian, Thai and Vietnamese). Many contain hidden sources of fish (e.g., kimchi made with fish sauce) and —even if you order a fish-free dish, there is high risk of cross-contact.

Allergens are not always present in these food and products, but fish can appear in surprising places. Again, read food labels and ask questions if you’re ever unsure about an item’s ingredients.

Carrageenan, or "Irish moss,” is not fish. It is a red marine algae used as an emulsifier, stabilizer and thickener in many foods like dairy foods. It is safe for most people with food allergies.

Fish allergy is sometimes confused with iodine allergy because fish is known to contain the element iodine. But iodine is not what triggers the reaction in people who are allergic to fish. If you have a fish allergy, you do not need to worry about cross-reactions with iodine or radiocontrast material (which can contain iodine and is used in some radiographic medical procedures).