Remarkable deficiency in fish production, due to many factors including water pollution and parasitism, was evident. The common parasitic ciliate Ichthyophthirius multifiliis is one of the most important protozoan pathogens of freshwater fish throughout the world. Examination of freshwater fish representing four different species of Tilapia from the River Nile revealed higher percent of infection in Oreochromis niloticus, followed by Oreochromis aureus, Sarotherodon galilaeus and Tilapia zilli. Upon the initial natural infections, typical white spots characteristic of "Itch" appeared on Oreochromis niloticus and Oreochromis aureus, while Sarotherodon galilaeus and Tilapia zilli showed only non-specific signs of mild skin irritation.