Abstract: In parasitological investigations on some fishes of Parishan Lake in 2008, totally 76 numbers of fish from 6 species were examined. They were as follows: Cyprinus carpio, Barbus luteus, Barbus grypus, Carassius carassius, Liza abu and Mastacembelus mastacembelus. The fishes were collected seasonally and were transported alive to the aquatic laboratory in Islamic Azad University of Kazerun. According to the results, there were eight different parasites collected; five species of Myxozoa including: Myxobolus karuni, Myxobolus persicus, Myxobolus mulleri, Myxobolus bramae, Myxidium pfeiffer and three species of protozoa including: Ichthyophthirius multifiliis, Trichodina nigra, Trichodina puytoraci. During this study, Barbus grypus is introduced as new host for Myxobolus bramae and also Barbus luteus for Myxobolus mulleri, Myxidium pfeiffer and Trichodina nigra; The Trichodinads were recorded for the first time from Iranian freshwater fishes. No parasites were seen from examined Mastacembelus mastacembelus.