A cross-sectional study was conducted in different Lakes of South Wollo Zone of the Eastern Amhara Regional State of Ethiopia, from November 2018 to April 2019, with the aim of determining the prevalence and identifying the species of internal and external parasites from fresh water fish. A total of 506 Oreochromis niloticus and 215 Cyprinus carpio fish (n=721) were collected and examined for the presence of fish helminthes parasites. The prevalence of parasites in Lake Luggo, Ardibo, Golbo and Maibar were found to be 49.4%, 41.7%, 46.7% and 36.0% respectively. The overall prevalence of parasites of both fish species was 45.1%. The prevalence of parasites in O. niloticus was found to be 42.3% and that of Cyprinus carpio was 51.6%. There was statistical significant difference (X2=5.311, p= 0.021) between the two fish species in the overall prevalence of the parasite infestations. However, the difference in prevalence of parasites among study site was not statistically significant X2=3.263, p=0.064). In this study, five parasites namely Contracecum spp and Camallanus spp. (nematoda), Clinostomum spp., Diplostomum spp. (eye fluck) and Posthodiplostomum spp. (Black spot), (trematoda) were recovered with a prevalence of 29.4% (n=212), 13.2% (n=93), 25.3% (n=183), 2.5% (n=18), and 14.8% (n=107) with the overall prevalence of 45.1% (n=325) respectively. There was a statistically highly significant difference (X2=126.504, p=0.000) in the prevalence and distribution of parasite between the study area. No significant variations (P>0.05) in prevalence of helminthes parasite were noticed in relation to sex and study sites of fishes, but in case of age significant variation was observed (p<0.05) except in which prevalence was observed to significantly increase when age is decreased. Among the parasites recovered Clinostomum spp. and Contracaecum spp. have been reported to be zoonotic and therefore, more research is required to characterize them and determine their zoonotic importance. Meanwhile, the present study revealed that helminthes parasites are among the major health constrains of fishes in the aforementioned water bodies, demanding an urgent control Intervention.
