From Steve Schweitzer's A Fly Fishing Guide To Rocky Mountain National Park, flyfishingrmnp.com:
Colorado River to 9,000 ft:
Columbine Creek can best be described as a small feeder creek bubbling through dense cover. The brook trout population is sparse in spots and the fish are on the small side, ...
From 34, take CO 66 past Green Ridge Campground, over Shadow Mountain Dam to the East Shore Trailhead. An easy short day hike takes you along the east shore of Shadow Mountain Reservoir and the out-flowing Colorado River. Despite the ominous look of the trail profile, the trail traverses only 227 feet in altitude from the lowest point of the trail to the highest. Midway through the hike, the official trail takes the high road and veers off into the woods presenting a perfect opportunity to spot moose. Following the shoreline takes you on East Shore Trail. Both trails reconnect below the foot bridge crossing along the Colorado River outlet of Shadow Mountain Reservoir. Pale Creek may contain seasonal fish but is generally considered barren.