RESUMEN
The relationship between the protozoal infections of fish and the water quality of three sampling sites representing two different ecosystems was investigated. Sixteen physico-chemical parameters were analyzed namely; temperature, turbidity electric conductivity, salinity, PH, alkalinity, hardness, sulphate, phosphate, ammonia, nitrite. Nitrate, dissolved oxygen [DO[2]], biological oxygen demand [BOD], chemical oxygen demand [COD] and organic matter. There was a gradual increase in the incidence of parasitic protozoa in the different sampling sites, which could be related to the gradual decrease in DO[2] and the increase in the other parameters of water analysis. A positive correlation [R[2]] was found between the incidence of trichodina sp. and Apiosoma sp. and water turbidity. Also a positive correlation [R[2]] value was found between incidence of apiosoma sp. And concentrations of phosphate, nitrite and ammonia. While DO[2] correlated negatively with the incidence of both of trichodina sp. And apiosoma sp. Incidence of Henneguya sp. and trypanosome sp. Showed no relation with the different water quality parameters