The current survey is the primary documentation of the metazoan parasite fauna of freshwater fishes of River Godavari, Andhra Pradesh state. The study was conducted for a period of four years i.e. 2005 to 2009. The Prevalence, mean intensity and mean abundance of metazoan parasitic infection and different community characteristics, along with the qualitative correlation of metazoan parasites among species and families of the 20 freshwater fishes belonging to thirteen families of River Godavari, Rajahmundry, Andhra Pradesh were determined. Metazoan parasite fauna of this geographical area is much diversified with 62 species of parasites belonging to 7 major taxa: eight species of monogeneans, 28 digenea of which 20 adult digeneans and 8 larval trematodes, 7 cestodes, 11 copepods, 6 acanthocephalans, 1 nematode and 1 Isopod. Prevalence of infection ranged from 77.5% (M. armatus) to 4.4% (Sperata seenghala) and mean intensity from 89.3 (M. armatus) to 1.0 (Sperata seenghala). The infra and component communities of parasites were somewhat distinctive/ peculiar. The dominance pattern of the major taxa was in the order Digenea > Copepoda > Monogenea > Cestoda > Acanthocephalans > Nematoda = Isopod. Richest parasite fauna (n=12) was observed in Mastacembelus armatus followed by Clarias batrachus (n=10). The parasite fauna of C.batrachus and M.armatus was the most heterogenous with four and six parasitic groups respectively and that of L.rohita, the most homogenous with only two parasitic groups. The diversity of parasite fauna was the greatest in Mastacembelus armatus and least in Cyprinus carpio, Heteropneutus fossilis, Notopterus notopterus, Nandus nandus, Sperata seenghala and M. pancalus. The parasite faunas of M.vittatus and M.cavasius were very similar as both the hosts shared 5 species in common; C.punctatus and C.batrachus shared only two species in common. However, in spite of taxonomic nearness and the similarity of habits and habitats of 4 species of cyprinids (C.catla, C.mrigiala, L.rohita and C.carpio), their parasite fauna were qualitatively dissimilar of the 5 species of parasites encountered in them only 2 species was shared by the 2 host species. Similarly, M.armatus and M.aculeatus showed dissimilar parasite fauna with only 3 species shared in common by the two hosts. The cyprinid, Cyprinus carpio had its own characterstic component community of parasites consisting of only one species which was not shared by the the other three cyprinids. Similarly, the two mastacembelid species, M.armatus and M.panclaus had their own characterstic component communities and their parasitic communities were quite dissimilar. The richest parasite fauna was that of the family Mastacembelidae (n=17) followed by Bagridae and Clariidae and the poorest of Heteropneustidae, Nandidae and Notopteridae. The most homogenous parasite fauna was that of Clariidae and the most heterogenous parasite fauna was that of Cyprinidae. The results specify that the freshwater fishes of River Godavari also harbour a rich and diverse metazoan parasite fauna but not as rich and diverse as that of the marine counterparts from this area. The results also put forward that carnivorous/omnivorous fish species harbour richer and more heterogeneous component communities of parasites than herbivorous species implying the role of the feeding habits as a major deciding factor for the parasite fauna of fishes.
