Sacramento pikeminnow, Umpqua pikeminnow and northern or Columbia River pikeminnow

In addition to the Colorado pikeminnow there are three other species of pikeminnow in the United States: the Sacramento pikeminnow, Umpqua pikeminnow and northern or Columbia River pikeminnow. But each of these is a different species of pikeminnow, much like a cutthroat trout and rainbow trout are different species of trout or a grizzly and brown bear are different species of bear.

None of these other species has been known to grow to the size of the Colorado pikeminnow, which historically reached lengths of up to 6 feet. Also, each species of pikeminnow has a distinct appearance and behavior. For example, the northern pikeminnow originally evolved in lakes and appears to adapt easily to man-made reservoirs.

The northern squawfish also preys effectively on game fish, and often becomes the dominant species in reservoirs, despite biologists' efforts to limit their population size.

In fact, the northern squawfish are so prevalent in the Columbia River basin that they are considered a threat to salmon species. But again, these are distinct species of fish.