City of CT still trying to determine what killed 10,000 fish

It may have been the Koi Herpes virus that caused the death of more than 10,000 fish in Zeekoevlei.

An estimated 10,000 individual fish have been found dead in Zeekoevlei in Cape Town. Picture: Siyabonga Sesant/EWN.

CAPE TOWN - The City of Cape Town has been unable to determine the exact cause of death of more than 10,000 fish in Zeekoevlei.

Initially city authorities speculated the fish died of natural causes but cautioned residents to stay away from the water until it's safe to do so.

It may have been the Koi Herpes virus that caused the death of more than 10,000 fish in the area.

The municipality's Johannes Van Der Merwe says the same disease was present in the lake last year.

"The symptoms and conditions were the same as an outbreak in the same water body."

The Koi Herpes virus remains dormant in fish populations and is activated by environmental conditions such as hot weather and low water levels.

The area was cordoned off for several days to prevent residents from collecting and consuming the fish earlier this year.