This study provides a comprehensive examination of the present state of resources and fisheries in Meghna River (Nouhata Jalmahal) while highlighting the potential for enhancing existing fisheries management strategies to prioritize the conservation of fish biodiversity. The study was conducted using a pre-tested questionnaire and a direct catch assessment survey in the beel, as well as interviews with fishers, fish traders, locals, and the upazila fisheries officer. A total recorded 63 species of ichthyofauna were recorded in Nauhata Jalmahal, including 59 finfish, 1 puffer fish and 3 prawn species from 11 orders, 22 families. The Meghna River (Nouhata Jalmahal) exhibits a diverse fish population, with the orders Cypriniformes, Siluriformes, and Perciformes being the most prominent, contributing 36.51%, 22.23%, and 15.88%, respectively. The dominant family recorded was Cyprinidae (36.51%), followed by Bagridae (7.94%) and Channidae (4.76%). In terms of biodiversity indices, the Simpson dominance (C), Pielou’s evenness (J), Shannon-Weaver diversity (H), and Margalef’s richness (d) values were observed to be 0.91, 0.31, 2.98, and 9.45, respectively in December; 0.922, 0.43, 3.12, and 8.74 in January; and 0.897, 0.275, 2.87, and 8.56 in February. These findings indicate that the Meghna River (Nouhata Jalmahal) is a valuable open waterbody, potentially serving as a significant fishery and gene bank  resource. However, certain threats, both natural and anthropogenic activities, were identified during the experimental period. Therefore, it is essential to implement conservation measures to safeguard this precious resource.  Furthermore, the adoption of ecosystem-based fisheries management practices with the active participation of local communities is strongly recommended for ensuring the conservation of these water bodies.