The authorities in Uganda are investigating the cause of a large-scale death of fish on Lake Victoria - Africa's largest fresh water reservoir.
The fisheries ministry has warned the public not to eat the dead fish and to instead bury them.
Photos posted on social media by local residents show dozens of lifeless fish washed up ashore at Lake Victoria, as well as Lake Kyoga and River Nile.
Officials say the deaths may be caused by a drop in oxygen levels.
"Preliminary investigations have ruled out fish poisoning," Uganda's fisheries ministry said in a statement.
"It is suspected that the recent storms on the lakes caused mixing of the different waters thereby reducing the oxygen levels in the lake."
A full report by a team of experts that was earlier dispatched to the area is expected later on Monday.
"The most likely explanation is drop in oxygen levels" caused by recent flooding and water hyacinth weeds, ministry official Joyce Ikwaput Nyeko was quoted as saying by local media.
The ministry said the only affected species was the Nile perch, a staple in many Ugandan households.
The Nile perch - which can grow to weigh more than 100kg (220lb) - is believed to be sensitive to oxygen levels below two milligrams per litre of water, the BBC's Patience Atuhaire in Kampala reports.
"The fishing community and general public along the lake shores is... advised to pick the dead fish and bury it to reduce the stench," the ministry said.
But it also urged the public "to disregard the audio circulating on social media calling upon people to stop eating fish as the fish from the regular catches can easily be distinguished from the floating dead fish".
Lake Victoria is a vital resource shared by Uganda, Kenya and Tanzania.
In 2017, scientists warned that Lake Victoria was under threat of dying.
They blamed overfishing and pollution for severely damaged fish stocks.