Much of the Capitol Reef region is considered “high desert,” with an average of 8 inches (20.3 cm) of precipitation a year. Despite this classification, there are a few perennial (year-round) water sources, like the Fremont River and Sulphur Creek, that can support fish populations. The park is home to several species, some native and some non-native or introduced.

Non-native species are those that live outside their native range or typical habitat. Non-native animals that spread into natural areas and compete aggressively with native species for resources are referred to as invasive. Invasive species can displace native species, disrupt food chains, and alter nutrient cycles.

A complete Wildlife Checklist can be downloaded.

Although the lower reaches of the Fremont River through Fruita and downstream do not support a sport fishery, reaches upstream of Fruita in the Fremont River gorge do support brown trout. Brown trout is a non-native fish species which can be kept as long as it meets the legal requirements set forth in the Utah Division of Wildlife Resources fishing regulations.

two photos: close up of hand holding two fish, showing unique shaped mouth; three speckled fish with faint red side stripe in water.
Left: Biologist holding two flannelmouth suckers. Notice the unique mouth shape.
Right: Three speckled dace by rocks.

Left: NPS Right: USFWS

Native Fish

Bluehead Sucker

Bluehead suckers (Catostomus discobolus) are native to the Colorado River system and are found in the Fremont River, Pleasant Creek, and Sulphur Creek. They are usually found in riffles of the streams. Bluehead suckers feed on algae, slime, and aquatic insect larvae. This species is included on the Utah Sensitive Species List. These benthic (bottom-dwelling) species have a mouth modified to scrape algae (their primary food source) from the surface of rocks. Bluehead suckers range in size from 3.9 inches (100 mm) to 20.6 inches (525 mm) with the average 15.7 inches (400 mm).

Flannelmouth Sucker

Flannelmouth suckers (Catostomus latipinnis) are native to the Colorado River system, including the Fremont River. They are herbivorous and ascend streams in the spring to spawn. In recent times, Utah flannelmouth sucker populations have been reduced in both numbers and distribution, primarily due to flow alteration, habitat loss/alteration. The species is included on the Utah Sensitive Species List. These benthic (bottom-dwelling) fish primarily eat algae, although invertebrates and many types of plant matter are also consumed. Flannelmouth suckers are one of the larger native fish, growing up to 28 inches (700 mm), although the average size is 19.7 inches (500 mm).

Mountain Sucker

Mountain suckers (Catostomus platyrhychus) are native to Utah's Bonneville Basin, as well as the Colorado River system. They are probably present, but unconfirmed, in the park. These benthic (bottom-dwelling) fish eat algae, higher plants, and occasionally invertebrates. Mountain suckers are small and usually 6-8 in (15-20 cm) in length.

Speckled Dace

Speckled dace (Rhinichthys osculus) are native to the Fremont River and other perennial streams in the park, where they are common and widespread. They prefer rubble-strewn riffle areas and feed on algae and other plant materials as well as small crustaceans, insect larvae, and small snails. These benthic feeders (they feed on the bottom), eat primarily insect larvae and other invertebrates, although algae and fish eggs are also consumed. Specked dace are small, with an average size of 4.3 inches (109 mm).

Mottled Sculpin

Mottled sculpin (Cottus bairdi) are a small native species found in the Fremont River. They are carnivorous, bottom feeders that consume insect larvae, crustaceans, small fish and snails. These fish spawn from late winter through the spring. Mottled sculpin have an average size of 3 inches (80 mm).

Roundtail Chub (Gila robusta) historically occurred in the Fremont River, but are considered extirpated (locally extinct). These fish often occupy pools and eddies, including swift, swirling water below rapids. They feed on algae, aquatic and terrestrial insects, invertebrates, and crayfish. Roundtail chubs can grow to 19 inches (49 cm) and weigh as much as 3 pounds (1.3 kilograms), but average 9.8-11.8 inches (25-30 cm).


Non-Native Fish

Utah Sucker

Utah suckers (Catostomus ardens) are native to the Bonneville Basin but have been introduced to other areas throughout the state, including the Fremont River drainage. Although native to Utah, they are not considered to be native to park waters. They are relatively abundant in Utah, especially in Bear Lake. These benthic (bottom dwelling) fish are capable of adapting to many different types of environmental conditions in both lakes and streams. Utah suckers consume plant and animal matter, with algae being a common food item.

Utah Chub

Utah chub (Gila atraria) are native to the Bonneville Basin of Utah, where they were introduced into the Colorado River system and occur in the Fremont River. They are generalized feeders, consuming higher plants, algae, terrestrial and aquatic insects, snails, crustaceans, and small fish. These fish spawn in July.

Redside Shiner

Redside shiners (Richardsonius balteatus) are native to Bonneville and Columbia River basins, where they were introduced into the Colorado River system and are common in the Fremont River. They feed on small aquatic insect larvae, crustaceans, and some plant debris. These fish spawn in late June.

Southern Leatherside Chub

Southern leatherside chub (Lepidomeda aliciae) are native to the Bonneville Basin of Utah, where they were introduced into the Colorado River system and occur in the Fremont River, Pleasant Creek, and Sulphur Creek.


Bluegills (Lepomis machrochirus) are not native to Utah and are occasionally found in Halls Creek where they migrate from Lake Powell. They feed on mollusks, crustaceans, insect larvae, and occasionally on small fish and aquatic plants. These fish spawn in the spring and summer, with eggs hatching in about 2 days.

Rainbow Trout

Rainbow trout (Oncorhynchus gairdnerii) are native to western North America, but not to Utah. They are fairly uncommon but have been found in the Fremont River and upper reaches of Pleasant Creek. Rainbow trout eat primarily invertebrates, including insects, worms, zooplankton, and insect larvae.

Brown Trout

Brown trout (Salmo trutta) are native to Europe and western Asia and are found in the park in the Fremont River. They are piscivorous (fish-eating) but also consume amphibians, rodents, and invertebrates, including insects, snails, and crayfish.

Black Bullhead

Black bullhead (Ameiurus melas) are not native to Utah and are occasionally found in Halls Creek near the southern park boundary where they migrate from Lake Powell. Black bullheads are adaptable to a wide range of aquatic conditions but show preference for more quiet and muddier parts of a stream. They consume fishes, many types of invertebrates, plant matter, and detritus. These fish spawn from late spring to early summer.

two hands holding a large speckled fish with its mouth open.
Brown trout were likely introduced to Utah prior to the 1900s. This brown trout was caught in Yellowstone National Park.


Bluehead Sucker
A native Bluehead Sucker.


Last updated: May 7, 2024

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