Abstract: An oral vaccine composition for fish, and related oral vaccine delivery system and methods for making and using such oral vaccine composition and delivery system are described. The oral vaccine composition includes virus-like particles effective to mediate an immunoprotective response in a target fish species, wherein the virus-like particles are contained in biomass of an organism or cell culture in which the virus-like particles have been expressed, optionally further including (i) adjuvant effective to enhance the immunoprotective response of the virus-like particles in the target fish species; (ii) encapsulant protectively associated with the virus-like particles for selective locus bioavailability in the target fish species; and/or (iii) binding agent aggregating the ingredients of the composition with one another.