A four-year experiment to remove invasive fish from the Colorado River has reshaped its aquatic ecosystem, with notable declines in rainbow trout populations. Scientists undertook the project hoping to bolster the numbers of native fish, and initial signs indicate some recovery amongst those species. However, the overall success of the initiative remains unclear due to other environmental variables influencing the river's health. The removal focused on non-native trout that competed with and preyed upon indigenous fish. Researchers continue to monitor the river’s fish populations and assess the long-term impacts of the intervention. Conservation efforts are ongoing to ensure the protection of the Grand Canyon’s unique native fish.