Zebrafish interleukin-26 (IL-26) is a member of the IL-10 cytokine family and part of the IL-20 subfamily, which in mammals includes IL-19, IL-20, IL-22, and IL-24, and is known for its roles in mucosal immunity and host defense. While IL-26 biology is best characterized in humans, where it signals through the IL-20R1/IL-10R2 receptor complex and activates JAK/STAT pathways (primarily STAT1 and STAT3), zebrafish IL-26 is expected to function in regulating inflammatory responses at epithelial barriers such as the skin, gills, and gastrointestinal tract. In zebrafish, an established model for innate immunity and host–pathogen interaction studies, IL-26 likely contributes to antimicrobial defense, modulation of proinflammatory cytokine production, and coordination between innate immune cells and epithelial tissues during bacterial or viral infection. Given the optical transparency of zebrafish larvae and the availability of genetic tools, zfIL-26 provides a valuable system for visualizing cytokine-driven immune dynamics in vivo and for dissecting conserved IL-10 family signaling mechanisms. As such, zebrafish IL-26 supports both aquatic animal health research and comparative immunology studies aimed at understanding mucosal inflammation and infectious disease across vertebrate species.