Putah Creek Trout reports that Didymo or Rock Snot is currently found in the Bear River, Middle Fork of the American, Lower American, Little Truckee, Prosser Creek and other sierra waters. Didymo can destroy the habitat of the river by suffocating all of the invertebrates and covering the stream bottom. Anglers using these and other streams should take precautions to prevent transfer of this species to other waters. Remember to clean, drain and dry your boats and equipment after using these streams. We see our local waters as being clean but this report should sound an alarm that we are in danger of alien species invasion.