In this experiment, the influences of dietary garlic, onion, and sweet red pepper meals as herbal supplements were studied on some immunological parameters, total carotenoid content, and growth performance of male guppy fish (Poecilia reticulata) in the juvenile stage. The experimental diets were fed to fish as a control (0), and three other diets contained 20 g kg− 1 garlic, or 20 g kg− 1 red onion, and or 20 g kg− 1 sweet red pepper powders. The male guppies with the early weight of 0.642g ± 0.07 were stocked in twelve circular tanks (40 L capacity) at density of 30 fish per tank. Fish were fed to satiation the diets thrice daily. The results showed that dietary herbal additives induced a significant increase (P < 0.05) in some mucosal immunological parameters contained alternative complement (ACH50), total immunoglobulin (Ig), lysozyme, and total protein compared to control, which were the highest in the group with 20 g kg− 1 garlic powder. Also, various dietary herbal additives resulted in higher (P < 0.05) total carotenoids levels of lateral skin body and caudal fin of fish than control, which were the highest in the group with 20 g kg− 1 sweet red pepper. The growth performance and feeding indices enhanced significantly (P < 0.05) in experimental groups compared to the control. As a result, used herbal supplements had beneficial effects on immunological parameters and total carotenoid content of fish. So, the highest immunity and coloration was obtained separately at 20 g kg− 1 respectively with garlic and sweet red pepper meals.