The Colorado Greenback Cutthroat Trout is our, Colorado, official state fish and listed as threatened under the Endangered Species Act. Once widespread from the Arkansas River to the South Platte, sadly, due to overfishing, mining, and agricultural water diversion the Greenback now only occupies 1% of its historical river range, which is obviously a very bad thing if you love fishing, animals, or just love showing nature its proper respects.