If you want to reduce the chance of your tot (or small child to you non-English readers) of developing allergies then feeding them fish on a regular basis from an early ages seems to be the way to do it.
According to researchers from Sweden, children who regularly ate fish from the age of one had a significantly lower chance of suffering from asthma, rhinitis or eczema up to the age of twelve. The study involved nearly 3300 children and was carried out by use of parental questionnaires when the children were 1, 2, 4, 8, and 12 years old, and Serum immunoglobulin (Ig) E concentrations were tested at age 8.
The paper is published in the American Journal of Clinical Nutrition.