A cross study was conducted from November, 2015 to April, 2016 in Lake Lugo (Hayke), which is located in South WolloZone, northeast Ethiopia, with the aim of isolation and identifying the external parasites (crustacean and monogenean) from fresh water fish. A total of 124 randomly selected fishes comprising of 61 Oreochromis niloticus, 20 Clarias gariepinus and 43 Cyprinus carpio were examined for external parasites. The fish were examined thoroughly examined externally and sample of skin scraping and gills were taken for the presence of external parasite and lesion. From the total 124 fish species 23 (18.5%) fish species were infested with external parasite. From these infested fish species four external parasites which are three parasites of crustacean (Lerneaspp, Dolophusspp and Ergasilusspp) and one parasite of monogenean (Dactaylogyrusspp) were detected as the genes level. Prevalence of external parasites was higher in Clarias gariepinus (25%) followed by Cyprinus carpio (18.6%) and Oreochromis niloticus (18%) species. The statistical analysis showed that no statistically significant difference in among species, age and sex of fish (p>0.05). Based on this study crust aceans and monogeneans parasites have a great significance for the production of fish in the Hayke (Lake of Lugo) so it needs husbandry practice (water quality assessment and feed and feed delivery management), a serious control and preventive programs.