Fish Allergy

Learn about fish allergy, how to read food labels and how to avoid eating fish.

Finned fish is one of the most common food allergies. This allergy usually is lifelong. About 40 percent of people with fish allergy experience their first allergic reaction as adults.1

Salmon, tuna and halibut are the most common kinds of fish people are allergic to.

Finned fish and shellfish are not related. Being allergic to one does not always mean that you must avoid both.

Allergic Reactions to Fish

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 auto-injector (such as an EpiPen®, Auvi-Q™ or Adrenaclick®) with you at all times. Epinephrine is the first-line treatment for anaphylaxis.

Avoiding Fish

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.

Fish is one of the eight major allergens that must be listed on packaged foods sold in the U.S., as required by federal law. Read more about food labels>

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 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 cuisines (especially African, Chinese, Indonesian, Thai and Vietnamese)—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.

What About …?

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).

1Sicherer SH, Munoz-Furlong A, Sampson HA. Prevalence of seafood allergy in the United States determined by a random telephone survey. J Allergy Clin Immunol 2004; 114(1):159-65.