<p>This study evaluates the potential of high-density aquaculture to reduce carbon emissions and enhance economic benefit compared to traditional systems, focusing on <i>Ctenopharyngodon idella</i> farming. A carbon footprint analysis based on life cycle assessment (LCA) methodology, combined with field monitoring data, was used to quantify greenhouse gas emissions—specifically CO₂, CH₄, and N₂O—and assess economic benefits. The findings reveal that carbon emissions per unit of output (fish) in high-density systems are 33.5% lower than in traditional systems (5.07&#xa0;kg CO_2eq/kg) based on theoretical calculations. Empirical data further confirm this trend, showing emissions at 1.34&#xa0;kg CO_2eq/kg in high-density systems compared to 2.18&#xa0;kg CO_2eq/kg in traditional systems. The primary sources of emissions were identified as the decomposition of fish excreta and residual feed, contributing 41.4% and 50.4% of total emissions in traditional and high-density systems, respectively. Notably, CH₄ emissions in the high-density system (0.0038&#xa0;kg CO_2eq/kg) were significantly lower than that in the traditional system (0.0237&#xa0;kg CO_2eq/kg). Dissolved organic carbon (DOC) and ammonia nitrogen (NH₄⁺-N) as key drivers of CO₂ and CH₄ emissions, while higher available phosphorus (Olsen-P) concentrations were found to inhibit N₂O production. Meanwhile, the high-density aquaculture system achieved a net benefit of 5.75 RMB/kg, an increase of 79.0% compared to the traditional system (1.21 RMB/kg), while its economic benefit per kilogram of carbon emissions (1.55 RMB/kg CO_2eq) exceeded traditional aquaculture by 84.5%. These findings show that high-density aquaculture reduces carbon emissions and increases economic returns, offering insights for optimizing low-carbon, efficient systems and supporting the sustainable shift toward carbon neutrality in regional practices.</p> Graphical Abstract <p></p>