The Rare Native Fishes of the Colorado River Basin


The four federally listed species represent more than a quarter of all native species in the Colorado River basin and are essential indicators of ecosystem health. All Colorado River fishes evolved 3-5 million years ago in flashy, desert rivers.
If you encounter any of these fish please return them unharmed to the river.

U.S. Fish and Wildlife Service  biologist holds captured endangered bonytail

Bonytail (Gila elegans)
Bonytail is a highly endangered fish which has inhabited  the upper Colorado River basin for millions of years. Growing upwards of 22 inches or more and identified from other chubs by its pencil-thin caudal peduncle (forward of its tail), it’s the rarest of the four species, Little is known about what environmental conditions bonytail prefer and utilize.  U.S. Fish and Wildlife Service cultures and releases these rare fish into various locations on the Colorado and Green Rivers in the Upper Colorado River Basin.

Colorado pikeminnow (Ptychocheilus lucius)
The Colorado pikeminnow is the largest minnow in North America. Called the “white salmon” by early settlers, Colorado pikeminnow have been known to live up to 40 years old, historically reaching lengths upwards of 6 feet long and weigh 80 pounds! Today, researchers see adult Colorado pikeminnow 2 -3 feet in length in various locations throughout the upper Colorado River basin. 2015 population estimates there to be roughly 429 adults living in the Colorado River.

A photo of a humpback chub

Humpback chub (Gila cypha)
Named by its unique muscular hump behind its head, humpback chub primarily live in deep canyon areas in the upper Colorado River. This unique animal grows to roughly 20 inches, 2.5 pounds and has inhabited the basin for millions of years. The most recent humpback chub population estimates point towards roughly 3799 adults currently occupying the Colorado River throughout the Black Rocks and  Westwater Canyon reaches.

A fish biologist holds a razorback sucker showing of its keel

Razorback sucker (Xyrauchen texanus)
Found nowhere else on earth, razorback sucker is on of the largest species of suckerfish found in North America historically growing near 3 feet in length with a life span of over 40 years., Throughout the past 3 to 5 million years, these animals have thrives up and down the Colorado river. Razorback sucker are identified by its large keel behind their head which helps maintain its position in the fast flowing currents of the Colorado River.  2015 population estimates revealed approximately 8078 razorback sucker (larger than 300 millimeters) in the Colorado River.

Rare Native Fish are a Living Example of the History and Heritage of the Upper Colorado River Basin

For generations, these unique native fish have played an important role throughout the region. They were a valuable food resource for many early settlers moving west, as well as a plethora of terrestrial animals living alongside the river.  They are an important part of the heritage of the desert southwest. Above are photos of large Colorado pikeminnow captured in the early 1900’s on the Colorado and Green Rivers.