This unpolluted ecosystem represents a natural spawning place for the Danube salmon. It is rich with brown trout, Danubian roach, nase and large specimens of chub, but Danube salmons are most common. This fish feeds and breeds in the Rzav until it grows large enough to return to the Drina. The Rzav is one of the rare rivers in which you can catch several Danube salmons a day, using only simple fly fishing equipment for trout and grayling (dry nymph, streamers) or spin fishing techniques. The local Danube salmons can weigh 1 to 4 kg, but this mountain river often hides large specimen which can weigh over ten kilograms. The Rzav is an extremely preserved and clear river and these are the reasons that this river is an ideal place for spawning.