WEEDKILLER was found in a fish pond in which 8000 tilapia fish died in Nadi last October.
Fish farmer Peniasi Siga of Maqalevu in Nadi said the results of a test carried out by Fisheries Ministry officials showed his farm was allegedly poisoned.
"We received the test results on Monday and were told there was weedkiller in the water and it was the reason our fish was killed," he said.
Mr Siga said the test results were now with Nadi police.
"I was called by officers at the Nadi Police Station that they will start questioning people.
"I hope that with this investigation, justice will be carried out because we lost a lot of money through this."
The Nadi Police Station confirmed investigations into Mr Siga's case were continuing.
The farmer said since the five fish ponds were contaminated by the chemical, they have not been able to restart their business.
"We need help from the Ministry of Fisheries. From that time (October, 2012) until now, we have not found the money to start our business again.
"All we need is a fresh supply of baby tilapia and for our five fish ponds to be upgraded."
The former inmate said the business was started by his father who invested $100,000 in the farm.
He said his family and employees had not been able to find work since the closure of the farm.