# European freshwater fish die-offs

> Live situation record from CLSTR: https://clstr.news/situations/european-freshwater-fish-die-offs
> Updated: 2026-09-14T10:10:47.000Z. Sources: 13. Developments: 2.

Mass fish die-offs have been reported in various European waterways, linked to low water levels and oxygen depletion.

In Slovenia, more than ten tons of fish perished in Pristava Lake and the Pesnica River. Authorities attributed the event to drought conditions and water chestnut overgrowth, which increased oxygen consumption. Emergency responders utilized aeration and pumped approximately 3,600 cubic meters of water into the river to mitigate the crisis.

In the Czech Republic, hundreds of kilograms of fish, including catfish and carp, have died in the Morava River near Olomouc. Officials noted that low water flows prevent the dilution of pollutants, while recent rainfall has introduced agricultural fertilizers and impurities into the river system. Die-offs in this region are reported to occur primarily at night as oxygen levels drop.

## Timeline

### 2026-09-14: Morava River fish die-off reported in Olomouc

Low water levels and oxygen depletion are causing massive fish die-offs in the Morava River near Olomouc, Czech Republic.

8 sources. https://clstr.news/cluster/morava-river-fish-die-off-reported-in-olomouc

### 2026-08-23: Pristava Lake experiences mass fish die-off

More than ten tons of fish have reportedly died in Slovenia's Pristava Lake and Pesnica River, likely due to drought and low oxygen levels. Emergency crews worked to aerate the water to mitigate the impact.

5 sources. https://clstr.news/cluster/pristava-lake-experiences-mass-fish-die-off

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Cite as: European freshwater fish die-offs. CLSTR, https://clstr.news/situations/european-freshwater-fish-die-offs