Dead fish can be seen floating on an area stretching across dozens of metres on the lake.
Bad odour can be smelt from surrounding areas. The hot weather during the past few days has made the smell worse.
No visitors or local people are seen taking a walk or doing physical exercises around the lake as usual.
Most of the dead fish are tilapia.
Dozens of environmental workers arrived to collect the dead fish on June 27.
Workers said that the work would take several days due to the large amount of dead fish and rubbish on the lake.
This is not the first time the lake has reported mass fish deaths. The same problem occurred last June when local authorities concluded that hot weather was the cause.