This study examines the environmental consequences arising from pond “tra” fish breeding in the Mekong Delta. It explores technically and economically feasible wastewater treatment options for bringing water pollution down to an acceptable level in accordance with Vietnam’s environmental standards. Results show that the farmers’ practice of exchanging water between fishponds and outside water bodies is one of the main causes of surface water pollution in tra fish-breeding areas. Water sample analysis indicated that the COD concentration in tra pond water was 34 mg/l, exceeding the limit of <10 mg/l according to Vietnam’s surface water quality standards (TCVN 5942-1995, class A). The pollution load rate in terms of COD per kilogram of fish produced was 0.098.

To cope with the pollution situation more effectively, some technical pollution control options are proposed, of which the trickling filter technology was found to be the most cost-effective. Some policy recommendations to address the environmental pollution caused by pond tra fish production in the Mekong Delta are also given.