The Cyprinidae fish’s gills are considered the permanent habitat for Dactylogyrids spp., common monogenean ectoparasites. This study aims to investigate the impact of monthly aquatic ecological dynamics on the diversity of Dactylogyrus. Moreover, the prevalence and species richness were correlated as well. A total of 140 fishes, representing 12 species from the family Cyprinidae, were collected from the Lesser Zab River, located in the northeast of Altuon-Kopri town, Kurdistan Region, Iraq. The study was conducted from August 2022 to July 2023. The collected fishes included: Acanthobrama marmid (37), Alburnus mossulensis (9), Barbus (B.) sharpey (5), Capoeta (C.) damascina (7), C. umbla (3), Carasobarbus luteus (10), Carassus (C.) auratus (13), C. carassus (3), Chondrostoma regium (18), Cyprinion macrostomum (5), Cyprinus carpio (26) and Luciobarbus xanthopterus (4). They were inspected weekly for diversity variation and richness of Dactylogyridis with different aquatic parameters such as pH, temperature, total dissolved salts (TDS) and electrical conductivity (EC). The collected data revealed the presence of various Dactylogyridis species with different prevalence and species richness. Monthly variations revealed that the highest species richness occurslowermost the lowermostoccurred in March 2023, and the lowest was observed in September 2022. According to aquatic parameters, only water temperature shows a significant negative correlation according to the species richness (p<0.05). In contrast, the other parameters show no significant correlation in accordance to the different months, monthly aquatic mean level of pH, TDS and EC were not correlated with species richness and prevalence of Dactylogyridis spp.