Northern pikeminnow
(Ptychocheilus oregonensis)

The Northern pikeminnow, Columbia River dace or formerly Squawfish (Ptychocheilus oregonensis) is a large member of the minnow family, Leuciscidae. This predatory freshwater fish is native to northwestern North America, ranging from the Nass River basin to the Columbia River basin. A good deal of concern has been expressed regarding the impact northern pikeminnow populations may have on salmon in Columbia and Snake river impoundments.

Behavior and habitat
Northern pikeminnows can live at least 11 years, reaching up to 25 in (63 cm) in total length and 7.5 lb (3.4 kg) in weight. Female northern pikeminnow reach sexual maturity at about six years, males in three to five. A mature female can lay 30,000 eggs annually. Pikeminnow are adept predators, and in the Columbia and Snake Rivers, salmon smolts comprise a large part of their diets. Their populations have flourished with the development of the Columbia River hydropower system. The reservoirs have provided excellent habitat for pikeminnow and given them an advantage over depressed salmon and steelhead populations.

The northern pikeminnow has been shown to consume terrestrial insects, benthic invertebrates, other fish, aquatic insects, and plant matter.