What's In a Name?
Fathead minnow: refers to the enlarged head of breeding males
Pimephales (pie-meff´-al´-ezz) means "fathead"
promelas (pro-mell´-oss) literally "before black" in
Greek, possibly referring to the darkened head of the original specimen
Where Do They Live?
Fathead minnows are found in every drainage in Minnesota. It is the
most common species of minnow in the state. They live in many kinds
of lakes and streams, but are especially common in shallow, weedy lakes;
bog ponds; low-gradient, turbid (cloudy) streams; and ditches. These
habitats often have no predators and low oxygen levels. Fatheads are
noted for their ability to withstand low oxygen levels. Fatheads commonly
occur with white suckers, bluntnose minnows, common shiners, northern
redbelly dace, creek chubs, and young-of-the-year black bullheads.
How Big Do They Get?
How Long Do They Live?
Fatheads only grow to about 65-70 mm (2.6-2.8 in), and males grow bigger
than females. Most of these little fish live for only 1 year. Less than
20 % of 1-year-olds live to 2 years old. On rare occasions a fathead
makes it to 3 years old.
What Do They Eat?
Fathead minnows are considered an opportunist feeder. They eat just
about anything that they come across, such as algae, protozoa (like
ameba), plant matter, insects (adults and larvae), rotifers, and copepods.
What Eats Them?
In lakes and deeper streams, fatheads are common prey for crappies,
rock bass, perch, walleyes, largemouth bass, and northern pike. They
also are eaten by snapping turtles, herons, kingfishers, and terns.
Eggs of the fathead are eaten by painted turtles and certain large leeches.
Although humans do not eat fatheads, they harvest them as bait.
How Do They Reproduce?
Spawning season for the fathead minnow starts in late May to early June
when water temperature exceeds 16° C (about 60° F). It goes
into mid-August when the water temperatures begin to cool. About 30
days before a male begins to spawn, he develops dark coloration, breeding
tubercles (which resembles little horns) on his head, and a soft mucus-like
pad on his back between his head and dorsal fin. The male selects the
nest site, which normally is under an object such as a log, rock, stick,
pop can, or whatever may be dumped at the bottom of the waterway. The
bottom of the waterway is commonly made up of gravel or sand, which
easily can be moved. The male excavates enough of the bottom to be able
to fit easily under the nest object. He then defends it aggressively
from all other fatheads. Often females have to be very persistent to
gain admission to the nest. Once the female enters the nest she turns
upside down and lays her sticky eggs on the underside of the nest object.
She then leaves to either spawn with another male or go back to where
she came from. After the female leaves the nest, the male then fertilizes
the eggs. The male not only guards his incubating eggs; he fans them
with his fins and massages them with his back pad. This keep them clean
and well oxygenated. Other females may add eggs to the nest as the spawn
season goes on. The male continues his care until all of the eggs hatch.
Females produce clutches of eggs (groups of eggs that become ready for
spawning at the same time). Each clutch may contain 80-370 eggs. Most
females probably spawn several clutches in a season. We do not know
the actual number. The embryos hatch in about 4-6 days.
Conservation and Management
Fathead minnows are probably the most abundant minnow in Minnesota,
and so they have no special conservation status. Fatheads are the premier
bait minnow in Minnesota and are collected from the wild by anglers
and commercial bait dealers. They also are reared in ponds for the bait
"Cool Fact": The fathead minnow was used in the past
as a form of mosquito control in many Metro Area ponds, ditches, and
History of Minnesota Fishes
Photographs by Konrad P. Schmidt and Donald Biemborn
Text by Nicole Paulson & Jay T. Hatch in cooperation with
the Minnesota Department of Natural Resources' MinnAqua Aquatic Program