Potamodromous
Migrating within fresh water, between parts of a river or between a lake and its rivers, as mahseer and many carps do.
Also: potamodromy
Potamodromous fish make their whole migration in fresh water. The golden mahseer moves up Himalayan rivers to spawn in clear, gravelly tributaries during the monsoon and back down in winter. In the Mekong, many species move from the Tonle Sap lake into the river and back each year, timed to the flood. Rohu, catla and mrigal also move to flooded plains to spawn in the monsoon. Dams block these movements just as they block salmon.