On January 7, Long Son Commune People's Committee (Ho Chi Minh City) said that it has identified the cause of mass fish deaths in cage farming households on the Cha Va River at the end of December 2025 and the beginning of 2026.
Testing 4 fish samples performed by the Sub-Department of Livestock and Veterinary Medicine of Ho Chi Minh City all showed that all samples were negative for the virus causing neurasthenia - a dangerous agent capable of causing epidemics on a large scale. At the same time, no dangerous parasites were detected on the tested samples.
Test results of farming water samples show that many environmental indicators are at unfavorable levels such as dissolved oxygen (DO) content only reaching about 3.0 mg/L - this is a low level and is assessed as a high risk factor causing fish to weaken and die. Or the salinity measured at 35‰, the NH4+ index approaches the permissible level, increasing stress and environmental toxicity for farmed fish.
Functional agencies assess that the above factors occurred in the context of inter-season weather, high day-night temperatures, low tides, standing water and high farming density, causing the water environment to decline rapidly.
Long Son Commune People's Committee also said that through review, about 25 households raising birdfish, anchovies and snakehead fish were affected. The total damaged output is estimated at about 158 tons of fish. The least household lost more than 4,000 fish, the most household lost more than 46,000 fish, causing heavy damage to people.
Immediately after the incident occurred, Long Son Commune People's Committee coordinated with functional forces to urgently collect and handle dead fish, not to let them be discharged directly into the river to limit environmental pollution. At the same time, strengthen propaganda and recommend that farmers closely monitor the quality of water sources, strengthen ventilation, clean cages and rafts, reduce farming density and promptly report when abnormal fish deaths are detected.
