Abstract: This study was conducted to evaluate the effect of dietary prebiotic Immunogen on the reproductive performance of a livebearing ornamental species, platy (Xiphophorus maculatus). Fish were fed under 4 regimes, 0% (A), 0.5% (B), 1% (C) and 1.5% (D) Immunogen mixed diet for a period of 26 weeks. Results indicated that Gonadosomatic Index (GSI), fry production, relative fecundity and fry length were significantly (p<0.01) higher in group D as compared to the control (group A) and other experimental groups. The percentage of deformed fry was not significantly affected by the various dietary treatments (p<0.05). Moreover, fry survival (%) was found lowest in control group. With the observed results, researchers are able to conclude that female platy-fish broodstocks benefit from inclusion of prebiotic immunogen in diet during their reproductive stages.