The present study surveyed the natural concurrent parasitic-bacterial infection among some fish species from different aquatic environments in Egypt. A total of 379 moribund freshly dead fish with different body weights were collected in 2019; 259 (Oreochromis niloticus and Tilapia zilli) freshwater fish were seasonally taken from the Nile River in Giza, while 120 (T. zilli and  Solea aegyptiaca) marine water fish were collected in summer from Manzala and Qaroun Lakes at Fayoum province. Fish were examined for parasites. Bacteria were isolated from infested fish and identified at the genus level. Examination of freshwater fish exposed the presence of Clinostomum and/or Euclinostomum spp., while only Pseudomonas was isolated. Between seasons, summer''s both total infestation and total concurrent infection prevalences of 43.59% and 73%, respectively, were significantly the highest. Within parasite, the prevalence of Clinostomum infestation alone with 77.27%, 70.31% and 76.09% for winter, spring and autumn, respectively, was higher than summer with only 47.06%. Conversely, the prevalence of concurrent infection in summer for Clinostomum alone (63%) was significantly higher than in winter (18%). For both of parasites together, infestation prevalence in summer with 26.47% was significantly the highest. Examination of marine water fish revealed the presence of at least one isopod, and Vibrio, Pseudomonas and Aeromonas were isolated. The prevalence of concurrent Vibrio infection (64.0%) was significantly higher than 26.0% and 52.0% for Pseudomonas and Aeromonas, respectively. Total infestation prevalence in freshwater (90.35%) was significantly higher than in marine water (41.7%). Alternatively, the total prevalence of concurrent infection in marine water (96.0%) was significantly higher than in fresh water (56.41%). In conclusion, the light was spotted on the effect of increasing temperature and the high burden of natural parasitic and bacterial concurrent infection. Further investigation is required to refine the relationship between parasites and bacteria for more epidemiological knowledge that aids in disease prevention and control.