Fish allergy
Finned fish such as salmon, tuna and cod are one of the nine major food allergens in the US. The allergy often first appears in adults.
What it is
Fish allergy is an immune reaction to proteins in finned fish. Fish proteins bind to IgE antibodies, which sets off the reaction.5 For the US labeling law, FDA counts three groups as fish: bony fish such as trout, flounder, bass, salmon, tuna and cod; cartilaginous fish such as sharks, rays and skates; and jawless fish such as hagfish and lampreys.3
Finned fish allergy affects about 1% of people in the US. In one study, salmon, tuna, catfish and cod were the fish people most often reported reacting to.5 Unlike most food allergies, which begin in infancy or early childhood, fish allergy may not show up until adulthood.4 About 40% of people with fish allergy have their first reaction as adults.5
Fish and shellfish are different allergies. ACAAI says there appears to be no relationship between them, though a person can be allergic to both.4
Symptoms it causes
Fish allergy symptoms follow eating fish, and they range from mild to severe. ACAAI lists hives or a skin rash; nausea, stomach cramps, indigestion, vomiting or diarrhea; a stuffy or runny nose and sneezing; headaches; and asthma.4 Food allergy symptoms can begin within a few minutes to a few hours after eating.2
An allergy to finned fish is a frequent cause of anaphylaxis, a severe reaction that comes on quickly, can make breathing hard and can cause shock.4 Reactions are hard to predict, and a very small amount of fish can trigger one.5
Fish does not have to be eaten to cause a reaction. Fish proteins may be released into the air during cooking, and steam from cooking fish can carry them.45
Reading food labels
Fish is a major food allergen under US law, and labels must name the species of fish.1 The Food Allergen Labeling and Consumer Protection Act of 2004 (FALCPA) made fish one of eight major food allergens. The FASTER Act added sesame as the ninth in 2021.1 FDA enforces these rules for the foods it regulates; poultry, most meats, certain egg products and most alcoholic drinks fall under other agencies.2
The label has to name the fish at least once: in parentheses after an ingredient, or in a “Contains” statement right after or next to the ingredient list.1 FDA guidance says neither place can simply declare “fish.” The species must be named, such as bass, flounder or cod. When an ingredient comes from more than one species, each one is named, as in “gelatin (cod, haddock, pollock).”3
Statements such as “may contain fish” or “produced in a facility that also uses fish” are not required by law. FDA says they must be truthful and not misleading, and they cannot stand in for good manufacturing practices.1
Fish can turn up in less obvious foods. ACAAI and FARE name Worcestershire sauce, Caesar salad and dressing, barbecue sauce, imitation crab and other surimi products, fish stock in some Asian dishes, and fish gelatin, which is made from fish skin and bones.45 Carrageenan is a red seaweed, not a fish.5
Names on a menu are not always reliable. ACAAI notes that some restaurants may serve a cheaper fish in place of the one listed, and many fish look alike once filleted.4
Cross-reactions
| Can also react to | What happens |
|---|---|
| Other finned fish | More than half of people who are allergic to one kind of fish are also allergic to other kinds of fish.5 |
Symptoms it can cause
Related conditions
Guides
When to get help
Call 911 if someone
- Is short of breath, wheezing or coughing, or has a tight chest
- Has a tight throat or trouble swallowing
- Has swelling of the lips, tongue or the back of the throat
- Feels dizzy, faints or has a weak pulse
These can be signs of anaphylaxis, a serious allergic reaction that can begin very quickly. If someone is having a serious allergic reaction, call 911.
See an allergist if
- Allergy symptoms last for several months of the year
- Allergies bring repeated sinus problems, a blocked nose or trouble breathing
- Over-the-counter remedies don’t control your symptoms
- Allergies or asthma get in the way of daily life
- You often wheeze, cough at night or after exercise, or feel short of breath
Based on ACAAI’s “When To See an Allergist” and MedlinePlus on anaphylaxis. General information, not medical advice.
Questions
If I’m allergic to fish, am I allergic to shellfish?
Not necessarily. ACAAI says there appears to be no relationship between fish and shellfish allergy, though a person can be allergic to both.4
Can you develop a fish allergy as an adult?
Yes. Most food allergies start in infancy or early childhood, but fish allergy may not appear until adulthood. In one study, as many as 40% of people with fish allergy had no problems with fish until they were adults.4
Can a food label just say “fish”?
No. FDA guidance says neither the ingredient list nor a “Contains” statement can broadly declare “fish.” The label has to name the species, such as bass, flounder or cod.3
Can cooking fish cause a reaction?
It can. Fish proteins may be released into the air while fish is cooking, so being near it can be a risk for people with fish allergy.4
Sources
- Food Allergies. U.S. Food and Drug Administration. Read on October 15, 2026.
- Food Allergies: What You Need to Know. U.S. Food and Drug Administration. Read on October 15, 2026.
- Questions and Answers Regarding Food Allergens, Including the Food Allergen Labeling Requirements of the Federal Food, Drug, and Cosmetic Act (Edition 5): Guidance for Industry. U.S. Food and Drug Administration. Read on October 15, 2026.
- Fish Allergy. American College of Allergy, Asthma and Immunology. Read on October 15, 2026.
- Fish Allergy. Food Allergy Research & Education (FARE). Read on October 15, 2026.