The present study investigated freshwater fish diversity in Saharanpur district, Uttar Pradesh, India, during January-April 2026. Fish samples were collected from rivers, canals, ponds, wetlands, and reservoirs using standard sampling methods. A total of 24 fish species belonging to 9 families and 5 orders were recorded, with family Cyprinidae being dominant (41.6%). River habitats showed higher fish diversity compared to stagnant water bodies. Economically important fishes such as Labeo rohita, Catla catla, and Cirrhinus mrigala were commonly observed. Biodiversity indices indicated moderate to high ichthyofaunal diversity and relatively stable ecological conditions. However, pollution, agricultural runoff, and overfishing negatively affected fish diversity. The study emphasizes the importance of conservation and sustainable fisheries management for freshwater ecosystems in Saharanpur district