The humpback chub (Gila cypha) is a federally protected fish that lived originally in fast waters of the Colorado River system in the United States.

[3] The humpback chub's population in the Colorado has been reduced dramatically, primarily due to habitat loss, such as the construction of Glen Canyon Dam.

The fish's status as an endangered species has inspired a number of costly and controversial management measures, such as altering the operation of Glen Canyon Dam and removal of non-native predators.

The young prefer shallow, low-velocity nearshore pools in the Little Colorado River, and progressively move to deeper, faster areas with increasing size and age.

[7] In the Colorado River in Grand Canyon, young-of-year are found in backwater and other near-shore, slow-velocity sites,[8] with similar ontogenetic tendencies.

[10] The population in the Grand Canyon has been previously infested with the parasitic copepod Lernaea cyprinacea,[11] and Asian tapeworm, Bothriocephalus acheilognathi.

The humpback chub's status as an endangered species has prompted elaborate and expensive programs to restore its numbers, largely by modifying the releases from Glen Canyon Dam, creating artificial floods to replicate historic conditions in the Colorado, and removal of non-native predators, such as rainbow trout.

[4] Effective April 20, 1994, seven reaches of the Colorado River System (totaling 379 miles) were designated as Critical Habitat for Gila cypha.

Federal officials have tried a number of experimental releases from Glen Canyon Dam in an attempt to replicate historic conditions and restore sandbars, beaches, and backwaters downstream.

The first flood began on March 26, 1996, when Interior Secretary Bruce Babbitt stood before a large gathering of media and opened the first of four outlet tubes to begin the imitation inundation.

Initially, it appeared that the flood was a success, with sandbars and backwaters created downstream, but as the dam's operations returned to normal, the Colorado ate away at the new habitat and reversed the gains.

[4] Introduced smallmouth bass have been a predatory threat to humpback chub above the Glen Canyon Dam, but had not been able to get beyond Lake Powell.

But as of 2022, smallmouth bass have been found below Glen Canyon Dam, possibly as a result of the low water level at Colorado River and Lake Powell.