This study aimed to evaluate and compare the efficiency of echinacea and garlic-supplemented diets as immunostimalants after different periods of application and after 4-month of withdrawal on some haematological and immunological parameters as well as the survival rate, growth performance and resistance of Nile tilapia (Oreochromis niloticus) to Aeromonas hydrophila infection and cold stress during the winter season through field hapa experiments.