Catfish Interleukin-8 (IL-8), also known as CXCL8, is a pro-inflammatory chemokine that plays a central role in the innate immune defense of teleost fish by mediating leukocyte chemotaxis, particularly neutrophil- and macrophage-like cell recruitment, to sites of infection or tissue injury. In commercially important species such as channel catfish (Ictalurus punctatus), IL-8 is rapidly upregulated in response to bacterial pathogens including Edwardsiella ictaluri, Flavobacterium columnare, and Aeromonas hydrophila, as well as viral and parasitic challenges. Functionally analogous to mammalian IL-8, catfish IL-8 activates chemokine receptor-mediated signaling pathways that promote inflammatory cell migration, respiratory burst activity, and antimicrobial responses in key immune tissues such as the kidney, spleen, gill, and skin. Elevated IL-8 expression is associated with acute inflammation and disease severity, making it an important biomarker for immune activation and pathogen exposure in aquaculture settings. In fish health and research applications, characterization of catfish IL-8 supports studies of host-pathogen interactions, mucosal immunity, vaccine efficacy, and selective breeding for disease resistance, contributing to improved disease management, productivity, and sustainability in catfish aquaculture systems.