The aim of this joint Croatian-French project was to introduce a new research topic into environmental research in Croatia and France, in the form of the introduction of modern instrumentation, i.e. the combination of HR ICP-MS and NanoSIMS, as a means of identifying increased accumulation of essential and non-essential elements in the tissues of native freshwater fish and for their intracellular monitoring, which is necessary for a better understanding of how fish deal with increased intake of toxic elements. The goals of this project were aligned with the significant improvement of natural sciences, teamwork and multidisciplinary cooperation around a common research topic.