More than 3,700 tilapia fish died in a floating cage on Lake Muhazi on Sunday, January 17, after three days of minimal oxygen through the cage, the Ministry of Agriculture has explained.

The cage had at least 10,000 fish of the same variety.

According to eyewitnesses, the fish started dying from 2am on Sunday, January 17 from the cage owned by Haguruka Dukore, a cooperative of 18 youths from Mununu Cell, Fumbwe Sector in Rwamagana District.

The ministry, which visited the area on Sunday morning to assess the problem, has concluded that heavy rains over the previous days caused erosion that disturbed the water and the submarine plants. This subsequently clogged cage nets and freshwater could not come in, causing shortage of oxygen for the fish.

The ministry stated on Twitter that, to solve this problem, they moved the cage to a side with deeper water, from 6.6 metres to 8.2 metres, with the wind also allowing the water coming in and out of the cage.

The cages were cleaned and the technicians removed other debris that could prevent the exchange of water between the cage and the surrounding water.

Aimable Musengamana, the president of the cooperative, said the fish that had been in the water for six months had matured and was set for harvesting on January 20.

"This is certainly a big loss, he said, mentioning that the previous round they had harvested around Rwf5 million.

"We have reinvested all the money we had, we had bought all the feeds and no money is left, this is a big loss for us,” he said.

Farmers were advised to regularly clean the floating cages, and to report to concerned officials as soon as they notice an unusual behaviour of their fish such as loss of appetite, among others.

The owners were told that they can eat or sell the surviving mature fish since it was found to be safe.