Aquaculture is one of Vietnam's fastest-growing industries, particularly in the Mekong Delta (VMD). While climate change affects pond productivity and economic gains, the industry itself has caused significant environmental issues, such as pollution and mangrove loss. Aquaculture ponds often rely on water canals that exchange polluted pond water with cleaner public water sources, like rivers. Unfortunately, wastewater is frequently discharged back into the same water sources, leading to persistent disease outbreaks and economic losses, especially for intensive farmers. These challenges highlight the need for adaptation strategies that preserve biodiversity, reduce pollution, and safeguard farmers’ incomes. Our research question explores the mechanisms that optimise farmers’ water usage (in terms of efficiency and fairness) while providing environmental benefits and additional financial returns from cooperation. We aim to provide insights on how to mitigate water pollution in aquaculture communities both from a farmer level and a public policy level (village, province levels). We examine policy mechanisms, such as fines and matching contributions, to improve farmer participation and ensure long-term sustainability of water usage. To analyse farmer cooperation, we implement a pen-and-paper, incentivized irrigation game experiment where farmers determine the size of the public good (water availability) and water usage in three provinces of the Mekong River Delta. We include unequal endowments to understand power differences in the industry. We show that the results vary by endowment and mechanism used to tackle threshold public good contributions.