Could the Oder mass fish die-off happen again?

Hundreds of kilos of dead fish have been found in canals connected to the Oder in Poland. Some fear last summer's catastrophic mass fish kill in the river that forms the border between Germany and Poland could recur.

source https://www.dw.com/en/could-the-oder-mass-fish-die-off-happen-again/a-65971681?maca=en-rss-en-ger-1023-rdf