Farmed fish have been dying in their thousands in the Mekong Delta's Dong Thap Province since last week, but worried residents still don't know why.
Dieu hong (red tilapia), a popular freshwater fish in the delta region, have been dying at nearly 200 fish farms along the local Can Lo River owned by 37 families.
There are so many dead fish that the farmers, unable to dry and process all of them, have sold them as feed to pangasius farmers.
Local residents estimate that more than 150 tons of fish worth over VND3.7 billion (US$190,000) have died so far.
"Any fish farmer here has mortgaged (the farm) for bank loans. Now with the fish dying, our labor and money are all gone. I just hope the government will support us cover part of the damage," said Nguyen Thi Thu Loan, one of the farmers.
The affected farmers have listed their damage and sent the information to different agencies asking for help, but local authorities are yet to respond or take any other action on the issue.
As of last Saturday (December 18), local agencies were yet to release results of testing done on water samples in the area.
But Do, a local who's had 35 of nearly 40 tons of fish die in recent days, said the river water was severely polluted and people had to row their boats several kilometers to the Tien River to bring water for their daily use.
There has also been talk that the fish was killed by wastewater released by a local drug firm called Domesco.
But Tran Ngoc Hao, director of the province's Department of Natural Resouces and Environment, said the accusation was "groundless" because the company has not finished its construction work in the province and begun operations.
In a similar case, environment agencies in Dong Nai Province, which neighbors Ho Chi Minh City, on Thursday (December 16) took water samples from fish farms along the Cai River, a tributary of the Dong Nai River, to investigate the death of around 13 tons of fish.
They also took samples from the wastewater pipe of Tan Mai Paper Factory located nearby, which was accused by the residents of having killed their fish.
The fish started to die on Tuesday (December 14) and Tran Van Sua, a local farmers' association official, said more fish could die in the coming days.