This study investigates the influence of fin morphology on predator-prey dynamics among selected fish species in Kwatan Giwa River, Niger State, Nigeria. A total of 192 fish samples representing eight species were collected biweekly from June to August 2024 at the Kwatan Giwa River fish landing site. Fish species were identified using standard taxonomic guides. Morphometric measurements of tail, pectoral, dorsal, and ventral fins were recorded using vernier calipers. Gut content analysis was conducted following modified Waraniak et al., (2019) procedures to determine dietary components and establish trophic relationships. Data were statistically analyzed to assess variations in fin structures and their ecological implications. The findings revealed significant interspecific variations in fin morphology. Species like Tilapia zilli and Auchenoglanis biscutatus possessed higher pectoral and ventral fin lengths, facilitating better maneuverability and habitat adaptability. Conversely, Siluranodon auritus exhibited consistently low fin measurements, indicating limited mobility and habitat specialization. The gut analysis revealed that Clarias gariepinus, identified as a piscivorous predator, had gut contents containing scales and remains of Tilapia spp, juvenile Synodontis, Labeo senegalensis, and Marcusenius senegalensis. In contrast, Tilapia spp, Labeo senegalensis, Auchenoglanis biscutatus, and Siluranodon auratus showed no fish remains in their guts, indicating non-piscivorous diets. The study successfully highlighted the relationship between fin size and predation strategies among selected fish species in the study area. However, Efforts should be made to protect the natural habitats of these fish species from degradation due to pollution, deforestation, and human encroachment.