The Kokra is true alpine river.Its spring is between 1100 and 1300 m altutude. In Spodnje Jezersko it unites with the Jezernica, which flows in from the Planšarsko jezero. Up to Preddvor is the Kokra a wild torrent.

In the lower part of the river, to the concrete bridge at the dam in Oljarica- in the village Britof- live mostly graylings, brown trouts, rainbow trouts and chubs, the chubs cannot be found upstream from Britof but the grayling can be spotted in the dam at Preddvor. The area upstream is mostly home to the indigenous brown trout. The fishing is allowed with  barbless artificial fly only-but it is possible to use shot up to 5 mm and a grip indicator that is appropriate for fly fishing.