The Kolpa river and its valley have by miraculous coincidence managed to avoid the fate of most European rivers. It still flows without obstruction, retreated into another long past period. In the still calm Kolpa valley, the red-spotted brown trout catch flies in the way that they always have. Behind a rock in the middle of a bubbling stream, the orange tail fin gives away the presence of a resting grayling. These two, together with the huchen, live in the upper reaches between Osilnica and Fara. Downstream from the inflow of the Kupica on the Croatian side the river is home to barbel, chub, Danube roach and nase. Grayling may be found as far as Dol. From Metlika downstream, there are no more salmonids, but pike and wels appear ever more frequently.