Fish is the most common causative food of food protein-induced enterocolitis syndrome (FPIES) in Southern Europe. In children with FPIES, the development of tolerance varies according to the culprit food and specifically fish seems to have a poorer prognosis than other solid foods. We sought to evaluate the fish-FPIES resolution rate in children. A descriptive retrospective analysis of children with fish-FPIES, followed during the last 20 years, was performed. The offending fish, age and symptoms at onset, the coexistence of atopic diseases and FPIES to other foods were registered. All the children included had undergone an oral food challenge (OFC) with the offending fish. We recorded those children that overcame their fish-FPIES and those that did not outgrow the disease. Seventy children were enrolled in this study (median age: 9 yo; IQR 6.4-13.8). Forty-two (60%) achieved tolerance to the offending fish with a median age of 4 years (IQR: 3-5). Among children ≤5 yo (n = 40), 35 (87.5%) developed tolerance; among 6-8yo (n = 14), 40% developed tolerance; and only 12.5% among those ≥9 yo (n = 16) developed tolerance. Twenty-eight children did not outgrow the disease (median age: 8.9 yo; IQR: 9-13.8). We did not find any statistical differences regarding the offending fish, presence of single vs multiple fish-FPIES, symptoms at the beginning, coexistence of other atopic diseases or the coexistence of other FPIES, between the children who overcame the disease and those who did not. One in five children with FPIES to fish will not overcome the disease during childhood.