Samples of the water have been sent for testing and the fish have been removed. The district administration has also ordered an investigation. Local people suspect the tank might have been poisoned over a business rivalry over fishing rights.
Collector K Veera Raghava Rao told NDTV: "We will take strict action once the reports come."
The dead fish started surfacing on Saturday evening and by Sunday morning, many fish had died and a strong stench had started coming from the tank, one of five at the temple.
Believed by devotees to be one of six homes of Lord Muruga, the tank is spread over an area of about 15 acres and is used by devotees for a ritual bath before the temple visit.
The water body impacts ground water table. Well known environmentalist Piyush Manush says "Normally if poisoned it is like end of the lake, restoration doesn't happen anyway as there's no flow of water. The only way is you empty the lake and wait for rains. There's no deterrent, nowhere in Tamil Nadu we've heard action being taken against or those responsible being arrested."
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