This study describes the first documented case of the tapeworm Atractolytocestus huronensis in common carp (Cyprinus carpio) from a small water reservoir in the Lublin region, Poland. A total of 28 tapeworms were found in the gastrointestinal tract of the examined fish. Molecular analysis of the COX1 and ITS2 gene regions showed a high similarity of sequences between the isolated tapeworm and previously identified A. huronensis strains from Slovakia, the USA, South Africa, and the UK, with similarities ranging from 97.87% to 99.25%. The COX1 sequence has been deposited in the GenBank database under accession number PV275034, and the ITS2 sequence is available under number PV265466. The observed clinical symptoms in the infected fish included skin redness and protrusion and redness of the anus. The gills of the fish were pale. Examination of the digestive tract revealed that its walls were edematous, and the mucous membrane showed small hemorrhages and congestion at the sites of tapeworm infestation. No visible changes were observed in the internal organs such as the liver, kidneys, and spleen. Bacterial infections were also identified, including Aeromonas veronii and Shewanella putrefaciens isolated from skin swabs, and Aeromonas sobria, Pantoea agglomerans, and Pseudomonas anguilliseptica identified in internal organs (kidneys and liver). This discovery represents the first report of A. huronensis in Poland and highlights the potential impact of parasitic and bacterial infections on the health of carp in confined water systems.