Piotr Biernat, spokesman of the Upper Silesian Waterworks Company, spoke about the special way this Polish lake is kept clean, “We are preserving the lake, because fish are the first cleaners of our water. As a first in Poland, and only here, we are using predatory fish to clean our water. Water purified by fish goes to the water treatment plant and then people can drink it.”
Eigh hundred thousand predatory fish are hunting other fish in Goczalkowice Lake. The fish will eat carp that stir up sediment, and make it harder to clean.
Lukasz Pszczelinski, head of the fishing farm in charge of the predatory fish, talked about how they deposit the fish, “We receive fish in bags with oxygen. They are approximately 3 to 4 centimetres long. We let them out in shallow and shrubby places, where the water’s the warmest and where there is most food.”