Over the past few decades, Indonesian freshwater aquaculture has intensified, raising many issues on the associated environmental impacts. In this study, a life cycle assessment (LCA) was used to assess the environmental performance of Indonesian giant gourami (Osphronemus goramy) aquaculture. We compared two contrasting fish production systems: a traditional monoculture (MoC) or a co-culture with the macrophyte Azolla filiculoides used as feed alternative to compounded pellets (CoC). Seven impact categories were considered: climate change, eutrophication, cumulative energy demand, land occupation, acidification, net primary production use (NPPU) and water dependence. The potential impacts were calculated in terms of 1 kg of fish produced by the systems and were also expressed in terms of surface area (m2 of the farm). Monte Carlo analysis was carried out to evaluate uncertainties in the assessed impacts based on data uncertainties for the systems. Results highlighted notable differences between the two production systems. CoC led to less impact relative to climate change, eutrophication and NPPU per kg of fish produced. These differences were even greater when reporting the impacts per surface area. Nonetheless, the main contributors of the seven impact categories remained constant between the two production systems (CoC and MoC). Overall, our findings suggested that using floating macrophytes as alternative feed resources, even in relatively low proportions, can improve the environmental performance of giant gourami production.