In September, a survey was conducted to assess fish communities in three post-mining lakes, including Lake Medard, a key monitoring site for the ProCleanLakes project. This activity aims to provide critical insights into the health and progression of aquatic ecosystems formed through the reclamation of opencast lignite mines in the heavily impacted landscapes of northern and the northwestern Czech Republic. Using CEN methodology to analyze fish community composition, abundance, and biomass, the survey results will offer an important evaluation of these lakes in line with the requirements of the Water Framework Directive. Importantly, these findings will be cross-referenced with data from similar European lakes and reservoirs, housed within the BC CAS (Biology Centre of Czech Academy of Sciences) database, to pinpoint primary ecological stressors and establish benchmarks for ongoing ecosystem management. This comprehensive, cross-site analysis is essential to advancing our understanding of aquatic ecosystem recovery in disturbed landscapes across Europe and will be used for evaluation the ecological quality of demonstration sites of the ProCleanLakes project.