A predatory species, the Colorado pikeminnow feeds on crustaceans, such as copepods and water fleas as a juvenile, then moves onto aquatic insect larvae and small fish, including other minnow species, once fully mature (2). It lacks teeth in its jaws but has a pair of enlarged bones in the throat which possess structures known as ‘pharyngeal teeth’, used to process food. Adults use these sharp, cutting pharyngeal teeth to slice through their prey (6).
Warm water is required for spawning, egg incubation and juvenile survival, so the Colorado pikeminnow mates and lays its eggs in the gravel bed during July and August when temperatures exceed 18 degrees Celsius (7). The Colorado pikeminnow has a mating ritual in which a female, followed by males, swims to the bottom, normally over a crevice, and vibrates to release her eggs, a process known as ‘broadcast spawning’. The males will then swarm around her emitting sperm, trying to fertilise as many eggs as possible (7).
Following fertilisation, it takes about one week for the larvae to emerge from the eggs (3). The larvae then drift downstream to sheltered backwaters (7) where they remain for the next two to four years. The Colorado pikeminnow takes many years to reach full size and can live for up to 12 years (6).