Horsetooth Reservoir, located in the foothills just west of Fort Collins, Colorado, is a highly popular destination for anglers and outdoor enthusiasts. Spanning approximately 6.5 miles in length, it primarily serves as a water storage facility for the Colorado-Big Thompson Project. Its rocky shorelines, deep coves, and clear waters create a diverse aquatic environment that supports a wide variety of fish species, establishing its reputation as a premier fishery in Northern Colorado.
Apex Predators and Warmwater Sport Fish
The warm-water fishery at Horsetooth Reservoir is dominated by species highly sought after by sport anglers. Walleye are arguably the most popular target, known for their preference for deeper, turbid water and their excellent table fare. These fish thrive in the reservoir’s open water and are actively managed through regular stocking to maintain a healthy population that can reach sizes over 20 inches.
Smallmouth Bass are another prominent species, flourishing in the reservoir’s abundant rocky structure and numerous coves. These powerful fighters are often caught near the shoreline, especially in the warmer months, and fish over 12 inches are common, making them a key component of the near-shore fishery. Regulations are in place to protect the smaller fish, with a minimum size limit of 12 inches for possession, helping ensure the population’s sustained health.
The reservoir also hosts a population of Wiper, a hybrid cross between a White Bass and a Striped Bass. Wipers are prized for their aggressive fighting style and rapid growth, often schooling and feeding on smaller forage fish in the open water. These predatory hybrids, along with White Bass, contribute significantly to high-action fishing opportunities and are subject to a generous statewide limit of 10 fish total per day.
Managed Coldwater Species
Despite being a warm-water fishery in its upper layers during the summer, the reservoir’s substantial depth allows it to support cold-water species. Rainbow Trout are a consistent feature in the deeper, cooler sections of the reservoir, particularly near the dam or in the main body during warmer periods. These trout do not successfully reproduce in the reservoir’s environment, meaning their presence is completely dependent on continuous stocking efforts by Colorado Parks and Wildlife (CPW).
The CPW’s stocking program is designed to provide a put-grow-and-take fishery, where hatchery-raised trout are introduced to be caught by anglers. Cutthroat Trout and their hybrid cross with Rainbow Trout, known as Cutbows, are also stocked, adding variety to the cold-water options. These species generally inhabit the lower water column where temperatures remain suitable for their survival. Anglers targeting these trout often find success by fishing deeper water with lures or baits that mimic the forage species available in the reservoir.
Forage Fish and Other Inhabitants
Supporting the array of apex predators is a diverse community of smaller fish and non-game species that form the base of the food chain. Yellow Perch are a notable inhabitant, serving a dual role as both a panfish target for anglers and a crucial forage species for Walleye and other larger predators. The abundance of these perch is a significant factor in the trophy potential of the Walleye population.
Other fish that are less frequently targeted by anglers but are ecologically important include various species of Suckers and Common Carp. Suckers, like the White Sucker, are bottom-dwelling fish that help cycle nutrients in the ecosystem and provide a substantial food source for large predators. Common Carp are also present, utilizing the shallow, weedy areas and acting as active bottom feeders.
Additionally, the reservoir contains various panfish, such as Bluegill and Black Crappie, which are particularly popular with family anglers. These smaller game fish provide a consistent catch rate and are an indicator of the overall health and productivity of the reservoir’s aquatic environment.