The outcomes of the present study exhibited that feeding goldfish on RA-enriched diets stimulated the protease activity leading to enhanced f ish growth and feed utilization. Depending on the study findings herein, enriching the fish diets with RA (600 mg/kg feed) is adequate to maintain fish health and performance. Thus, it can be utilized as an environmentally safe and natural therapeutic agent for the treatment of anemia and stimulating the fish performance and welfare status. The dietary RA could also support the immune function for confronting ammonia toxicity via modulating the expression of immune-related and anti-inflammation genes. Future work is needed to elucidate the po tential role of RA and investigate its influence on other fish species.