The Nile tilapia (Oreochromis niloticus) is one of the most promising freshwater fish species for aquaculture in Indonesia and other tropical countries. However, one of the main challenges in tilapia farming is the frequent infestation of ectoparasites, which negatively affects fish health and growth, reducing farm productivity. Common ectoparasites found on farmed tilapia include Trichodina sp., Dactylogyrus sp., and Gyrodactylus sp., particularly when water quality is poorly managed. Poor water quality, including low dissolved oxygen, high concentrations of ammonia, nitrate, and nitrite, can increase the prevalence of ectoparasitic infections in tilapia, as it induces stress and the fish's immune response to pathogens. This study aimed to evaluate the effects of different feeding treatments on tilapia health and ectoparasite infestation. Conducted from February to March 2023 at the Bone Marine and Fisheries Polytechnic, the research used three feeding treatments: commercial feed, Azolla microphylla , and a combination of both. Water quality parameters were monitored weekly, and ectoparasite prevalence and intensity were analyzed using ANOVA and Duncan's test. Results indicated that poor water quality, particularly low dissolved oxygen, was associated with increased ectoparasite prevalence, particularly Trichodina sp. The study concludes that proper water management and controlled use of Azolla microphylla can help mitigate the prevalence of ectoparasites in tilapia farming.