"A detailed examination suggested it happened due to lack of oxygen," Fisheries Minister Abdul Gani Kohli said.
A technical team visited the area to get first-hand information and ascertain why hundreds of fish turned up dead two days ago, he said.
The Director Fisheries, Kashmir, and the Joint Director Fisheries, Kashmir Division, also visited the area.
The fish were examined and it was seen they were in distress.
"Samples of water and fish were collected for a detailed analysis. Lack of oxygen in the water column was cited as the reason," he said.