Rocky Mountain crews target non-native fish to restore threatened greenback trout

For more than 80 years, fish were deliberately introduced into the waters that would become Rocky Mountain National Park. According to the National Park Service (NPS), more than 20 million fish were stocked in waters that are now part of Rocky Mountain National Park between 1886 and 1968, most of them non-native trout. What was once intended to support recreational fishing eventually created challenges for native fish and aquatic ecosystems. In 2026, park managers are working to reverse some of those effects. As part of the Poudre Headwaters Project, crews treated waterways connected to the 14.3-mile Grand Ditch to remove non-native fish and prepare habitat for the recovery of the federally threatened greenback cutthroat trout.A long history of stockingFish stocking began in the area in 1886, before Rocky Mountain National Park was established. Colorado stocked fish into mountain waters to create and expand opportunities for recreational fishing.