Mule deer, elk, cottontail rabbit, coyote, ground squirrels, great-horned owls, and yellow-tailed weasel are common sights in the hills around the campsites for wildlife watchers at Rifle Gap. Visitors may also observe beavers sliding around the bends of East Rifle Creek and small lizards sunning themselves on the rocks. A diversity of reptile species is recorded in the area, including Utah milksnake, midget-faded rattlesnake and western yellow-bellied racer.
Many species of waterfowl visit the reservoir in both the spring and autumn. Great-blue herron and Canada geese frequent the reservoir to feed in early morning, and can be seen from a distance with the naked eye or up close through binoculars. Marsh hawks (northern harriers) sometimes nest in the marshes near the confluence of West Rifle Creek and the reservoir. At different times of the year, ospreys, golden eagles or bald eagles are present around the reservoir.
Many anglers are attracted to the excellent warm-water fishing opportunities at Rifle Gap, which include walleye and largemouth and smallmouth bass. The reservoir is also stocked with cold-water rainbow and German brown trout.