THE ANIMAL FILES

Northern pikeminnow

Ptychocheilus oregonensis

A “minnow” can grow into a predator of other fishes.

The northern pikeminnow is native to western North America, including the Columbia River system. Young fish use invertebrate foods before taking more fish as they grow, so its feeding role changes during development.[1][3]

Follow the evidence ↓
Northern pikeminnow
Image: David Starr Jordan · Commons · Public domain
Range
Western North America[1]
Young diet
Aquatic invertebrates are important[3]
Adult food
Other fishes[1]

Size changes the available meal

Juveniles feed extensively on larger aquatic invertebrates until they can readily swallow small fish. Adults are fish-eaters. Age and body size therefore matter when interpreting stomach contents or feeding observations.[3]

More than one river habitat

The species uses main channels, shorelines, tributaries and quieter side waters. It can move between conditions and ambush prey near transitions between slow and fast water.[3]

Eggs and schooling young

Spawning occurs over gravel in streams, with adhesive eggs deposited there. Parents do not rear the young; once able to swim, young fish show schooling behaviour. A group of juveniles is therefore not evidence of parental supervision.[3]

A COMMON MIX-UP

Does “minnow” guarantee a tiny plant-eater?

No. This species grows into a substantial predatory fish; a common group name does not specify adult size or diet.[1]

TRY A LITTLE REASONING

Why separate juvenile and adult samples in a diet study?

Reveal the explanation

Their use of invertebrates and fish changes with growth. Mixing ages can hide that developmental shift.[3]

Sources & editorial notes

Adapted and translated from the cited Wikipedia revisions, with source-linked reasoning. Image credit and licence are listed separately above.

Adapted and translated from Wikipedia contributors; exact revisions are linked below. CC BY-SA 4.0

  1. Wikipedia contributors — Northern pikeminnow (fixed revision; adapted and translated)
  2. NCBI Taxonomy — Ptychocheilus oregonensis (identity and classification)
  3. Oregon Sea Grant — Northern pikeminnow natural history

Last fact check:

One discovery leads to another

Common breamA young bream does not yet have the deep body of a mature one.Abramis brama ↗Common roachA silvery shoaling fish changes its menu as it grows.Rutilus rutilus ↗GoldfishA familiar fish with a learnable world.Carassius auratus ↗