⚡Video: Mass Fish Deaths in European River Blamed on Toxic Algae

The fish deaths down the river in Germany were only reported around two weeks later. Tonnes of dead fish have been pulled from the Oder river as the micro-algae at issue -- known as Prymnesium parvum, or golden alga -- produces a toxic substance that is lethal to fish and other aquatic organisms. A Polish-German expert group was subsequently set up to investigate.