AbstractThe Rhine may provide a classical example of faunistic changes due to Man‐made stress. Formerly a salmonid river, it was transformed into a ship‐canal. Steadily increasing pollution culminated in the 1960s and 1970s. An improvement of water quality in the 1980s was followed by an increase in abundance of several species and faunal diversity. Originally 47 species inhabited the Rhine; at present 40 indigenous and 15 introduced species live in the river, seven have vanished or have not been observed so far. Recent setabacks, like the Sandoz Accident in 1986 failed to eliminate any taxon. Protection of the indigenous fauna is to be linked with conservation of remaining environmental diversity, ecotechnical improvements, and new strategies in fishery management, which do not merely support only economic spec