A portion of Clear Creek and Fish Creek were treated last fall with rotenone to remove rainbow trout and rainbow-cutthroat hybrids before they could expand throughout the drainage and threaten the conservation population of Bonneville cutthroat trout. The target area included Clear Creek — from its confluence with Fish Creek downstream 2 miles to the Narrows — as well as Fish Creek, from its confluence with Clear Creek upstream about 5 miles. All other stream reaches within the drainage, including Fremont Indian State Park, were unaffected by the treatment and still have abundant numbers of cutthroat trout. The treated area was restocked with more fingerling cutthroat trout in fall 2021, but it will take a couple years for these fish to mature.