Fathead Minnow (Pimephales promelas)

The fathead minnow is a small, hardy, and widely cultivated member of the Cyprinidae family of minnows that is commonly used as bait, and it is an important forage species for gamefish. It is also commonly used in toxicity studies.

Identification

The fathead minnow has a stubby, deep, compressed body with a short head that is flat on top. The snout is blunt. The mouth is small and slanted and possesses pharyngeal teeth. The body is generally dull in color, being dark olive or gray above and fading to muted yellow to white below. The scales become larger toward the tail and smaller toward the head, and the lateral line curves downward and is incomplete.

There is a dark spot at the middle of the anterior dorsal rays, the caudal rays have dark outlines, and the leading edge of the pectoral fins is black. There is also a stout half-ray at the front of the dorsal fin. There are no barbels, but breeding males develop tubercles on their snouts and become darker.

Size/Age

Fathead minnows average 1.5 to 3 inches long and grow to only 4 inches. Most die in their third year.

Spawning behavior

Fathead minnows have an extended spawning period, from late spring into summer. It commences when the water temperature exceeds 60°F. They are nest spawners, often creating nest sites under floating or suspended objects or beneath logs or stones, generally in 1 to 3 feet of water. Males create the nests, herd the females into them, and guard the nests until the eggs hatch; several females may deposit eggs in one nest site, and the adhesive eggs hatch in 6 to 9 days.

Food

The diet of fathead minnows is mostly algae, as well as bottom detritus, zooplankton, and insect larvae.

Other Names

minnow; French: tête de boule.

Distribution

This species ranges widely (in part through introductions) across North America, from Quebec to the Northwest Territories and south to Alabama, Texas, and New Mexico, as well as in Mexico. It is most common in the Great Plains and scarce in mountainous regions.

Habitat

Fathead minnows prefer ponds and pools or slow-moving water in streams, creeks, and small rivers. They can tolerate muddy water and are occasionally found in roadside ditches.

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