First record of highly invasive Chinese sleeperPerccottus gleniiDybowski, 1877 (Perciformes: Odontobutidae) in the Elbe River Basin, Czechia

The Chinese sleeper ( Perccottus glenii ) has invaded European freshwaters and we present evidence of its first documented occurrence in the Elbe River basin in Czechia. The individual fish was caught by a fisherman and posted on social media. After immediately contacting the person in question, we obtained a live fish from him. The Chinese sleeper appears to have been present in interconnected ponds and streams for ten years and may have spread over a larger area. We recommend that eradication measures be implemented to prevent further spread. Statement of Significance The Chinese sleeper has invaded many European countries in the last 50 years, and it is expected to invade western Europe because of the favourable conditions for its establishment. This finding indicates that it could spread in the Elbe River Basin, which could have serious impacts on floodplain and wetland ecosystems. To prevent this scenario, eradication measures should be implemented.