Under this title research was carried out during 2018 and 2019 (August, 2018 and January, 2022) from Keenjhar Lake, Thatta, overall 844 specimens were collected. Sample was sorted out into fives pecies Thalla (Catla catla), mold (Cyprinus carpio), silver (Hypophthalmichthys molitrix), Morakhi (Cirhinus madrigals) and Rohu (Labia rohita). It was observed that the rate of parasitic infestation was higher in summer as compared to winter season. During present study pH value, temperature, and nature of water were the major factors affecting the population of parasites and reciprocally had an impact on the rate of infestation. The percentage of parasitic infestation among the species were calculated as Argulus 30%, Lernaea 20%,Trichodnina 20% and Chilodonella 15% and the parasites attack on the fishes Glulfam 20%, Silver carp 16% , Morakhi 11% , Thallah 5% and Rohu 4%.