Most of the studies investigating the structural and functional characteristics of fish IL-1β and IL-8 have been performed mainly with representatives of the Salmoniformes, Cypriniformes, Siluriformes and Perciformes orders, with no studies providing a detailed analysis of the structure and expression analysis under pathogenic infections of IL-1β and IL-8 of fish from the Characiformes order being found in the literature. The gene discussed is IL1B; the disease is infection.