Seasonal floodplains under private and public ownership in the Indo-Ganges river basin provide food and income for millions of people in Bangladesh. Floodplain ownership regimes are diverse, covering the whole spectrum from public to private ownership. The paper compares community-based fish culture projects in these floodplains and analyzes the institutional arrangements of three different Floodplain Management Committees (FMC). The paper aimed to understand the complex institutional relations that govern ownership, access, and control of the floodplains under community-based fish culture (CBFC) to increase fish production and the livelihoods of the poor. We followed the stakeholders representing the various institutions and organizations such as the Department of Fisheries (DoF), Department of Land (DoL), and FMC. Other important stakeholders were the lease-holders of public water bodies in the floodplains, private landowners, seasonal and professional fishers. The analysis demonstrates a significant increase of benefits to all stakeholders, including the poor, through the sharing of benefits derived from their involvement in the project. The willingness of different social classes to work together, the adoption of new technologies, and the societal embeddedness of local government institutions appear to be important inputs for policy making.