Invasive species threaten ecosystems in Erfurt and Thuringia

Invasive species are significantly impacting local ecosystems in Erfurt and throughout Thuringia, Germany. The release of pet goldfish into natural waters has led to the decline of native species, such as the Prussian carp, as the adaptable goldfish consume smaller fish and amphibian eggs.

Jens Düring of the Lower Nature Conservation Authority noted that goldfish can revert to wild forms and interbreed with native populations. While goldfish are not currently classified as an invasive species across Europe—allowing them to be legally traded—officials are advocating for their inclusion on invasive species lists to ban their sale and trade.

Other problematic species include the blueband goby, which reproduces rapidly and preys on the offspring of native species, and invasive crayfish. These crayfish pose a dual threat by competing with native populations and spreading crayfish plague, to which local species have no natural defenses.