They have probably done so for centuries, but the fish migration up the Verkmyraån north of Gävle has been a tourist magnet for the past 50 years.
It is not only roaches that migrate up the river, other fish species can also be seen in the shoal, which fight their way up the fighting spring river to spawn.
It is not allowed to catch the fish.
Hille fisheries conservation area has introduced a fishing ban.
See how the fish walk in the video.