• View of Grand Canyon National Park at sunset from the South Rim

    Grand Canyon

    National Park Arizona

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  • From Monday Through Thursday, Warmer and Drier Weather Is Expected

    Monsoonal weather patterns have moved into the Grand Canyon area decreasing fire danger. As a result, on Tuesday, July 8 at 8 a.m. fire managers lifted fire restrictions within Grand Canyon National Park. More »

  • Two Bats Collected in the Park Have Tested Positive for Rabies

    One on the North Kaibab Trail and the other at Tusayan Ruin/Museum. Rabies can be prevented if appropriate medical care is given following an exposure. Any persons having physical contact with bats in Grand Canyon National Park, please follow this link. More »

Grand Canyon’s Native Fish

illustrations of the eight Grand Canyon native fish.
Fish native to Grand Canyon, from left to right: humpback chub, razorback sucker, bluehead sucker, flannelmouth sucker, speckled dace, and the three extirpated species: Colorado pikeminnow, roundtail chub and bonytail.
Illustrations by Joe Tomelleri
 
Grand Canyon was once home to eight species of native fish. Only five of these species are found in the park today. Following the completion of Glen Canyon Dam in 1963, the fish assemblage in the Colorado River in Grand Canyon has shifted to non-native rainbow and brown trout in the stretches of river closest to the dam and above the Little Colorado River. Of the canyon's native fish species, only speckled dace remain truly common in the park, and they live primarily in tributaries which retain their natural characteristics more than the Colorado River.
 
Two species of Grand Canyon's native fish are listed under the Endangered Species Act. Humpback chub, which used to be abundant in Grand Canyon, has been listed as an endangered species since 1967. Razorback suckers are very rare in the canyon, and were listed as endangered in 1991.
 
Grand Canyon has a very distinctive collection of native fish. All eight native species belong to only two families: minnows (Cyprinidae) and suckers (Catostomidae). Six of the eight native species are found only in the Colorado River basin. This very high percentage of endemic fish species likely results from the geographic isolation of the Colorado River system, and the highly variable natural environments, flow and temperature regimes of the river and its tributaries. The Colorado River has the lowest diversity of native fish and the highest level of endemism of any river system in North America. The river's unusual native fish assemblage is as iconic a characteristic of Grand Canyon as its towering cliffs, other endemic species such as the Grand Canyon rattlesnake, and spectacular scenery.
 
Grand Canyon National Park is currently conducting a variety of projects to conserve and restore native fish populations, especially the endangered humpback chub, in the park [link to translocation page]. The National Park Service is also developing plans to determine the status of the razorback sucker, an endangered species that was thought to be extirpated from Grand Canyon until 2012, when several individuals were detected in the western reaches of the Colorado River close to Lake Mead.

Did You Know?

GRAND CANYON ROCKS

The more recent Kaibab limestone caprock, on the rims of the Grand Canyon, formed 270 million years ago. In contrast, the oldest rocks within the Inner Gorge at the bottom of Grand Canyon date to 1.84 billion years ago. Geologists currently estimate the age of Earth at 4.5 billion years.