(De Haan, 1849) continues to spread in the Danube: first records in Germany and Hungary

This article presents the first records of the non-native Asian caridean shrimp Macrobrachium nipponense in Germany (Racklau Harbour, Passau) and Hungary (Lipót, Szigetköz floodplain), both discovered in 2023. Based on initial monitoring, both populations appear to be already established, and may serve as source populations for further spread, particularly downstream along the Danube River. The article explores the potential for upstream expansion from the lower Danube, where the species has been recently reported, as well as possible introduction pathways. We examined its ecological roles and potential impacts, which could be significant. Given the lack of effective eradication methods, efforts should prioritise minimising—and ideally preventing—further human-assisted spread. This should be underpinned by general environmental education and responsible pet ownership, potentially including a market ban, given the species' characteristics and its temperature tolerance across much of Europe. A deeper understanding of its interactions with both native and non-native species is needed. We call for intensified monitoring, particularly in suitable habitats such as harbours, using both conventional and eDNA methods to gain insights into its potential future distribution, and to reconstruct introduction pathways to inform management strategies.