Anyone had experiences with any allergy to codfish?

Food allergy. The most common food allergies are to peanuts, tree nuts, milk, soy, egg, wheat and seafood and fish. Among fish allergic patients, cod allergy is fairly common.
Absolutely. Fin fish are one of the 8 common allergens. It is used in many places you may not expect as well, so i would be very careful reading labels and avoiding. If you haven't seen an allergist to confirm the diagnosis, i would recommend doing so to avoid unnecessary changes in diet.