The study evaluates the use of silage acid devil fish (Pterygoplichthys spp.) as a protein supplement in finishing beef cattle, addressing the protein scarcity and high cost of traditional sources. Eighteen bulls were fed diets with varying levels of devil fish silage for 60 days, showing no significant differences in daily weight gain and feed efficiency among treatments. The results indicate that devil fish silage is a viable and eco-friendly alternative for enhancing cattle nutrition without negatively impacting animal health.