Human activities move many species out of their native ranges, where they establish and have substantial ecological effects on native communities. A group of invaders with particularly important ecological effects are crayfish. The large sphere of action for crayfish invaders are European inland waters, where native crayfish stock were depopulated in 19th century due to crayfish plague. Apart from plague, other negative factors include pollution of surface waters, habitat alterations, competition with non-native species, or predation. In accordance to native species conservation, the knowledge about crayfish invaders (distribution, life cycle, ecology) is important to assess their invasive potential and develop an effective management to suppress their spreading. Orconectes limosus is actually on of the the most distributed and actively spreading invasive crayfish in Europe.