What do they look like?

The bluntnose minnow is a very small silver fish, long and thin with a dark stripe from snout to tail. At the bottom of the tail the stripe becomes a dot. Upperparts are slightly olive while sides are bluish. The name "bluntnose" refers to the rather flat head and snout. During the breeding season, males become darker, with a silver bar behind the gill cover (opercle), and grow 16 bumps in three rows on their head.

Where in the world do they live?

The bluntnose minnow is found only in the Nearctic region. They occur from southern Quebec and Manitoba south to Louisiana, west to the Mississipi River drainage (but not the Mississippi River itself).

What kind of habitat do they need?

The bluntnose minnow is a freshwater fish that lives its entire life in the water. Bluntnose minnows prefer living in clear, rocky streams and creeks that are small to medium in size. They also occur in natural and man-made lakes.

How do they reproduce?

During the spawning season, males' heads grow darker and their bodies become bluish. They also develop three rows of bumps (called tubercles) on their heads. Females release masses of eggs which stick to the underside of rocks or floating logs. The eggs are therefore protected while the male fertilizes them. Depending on the temperature of the waters, eggs may hatch into baby fish (called fry) in 8 to 14 days.

The male fish take care of the eggs and guard them until they hatch.

How long do they live?

The maximimum recorded age for a bluntnose minnow is five years, this was probably a captive individual. In the wild, two years is a more realistic lifespan.

How do they communicate with each other?

During breeding season the males use at least two methods of communication. First, their physical appearance changes (as described in the reproductive section). Second, males make a variety of pulsed sounds when acting aggresively with other males. It is not known if these sounds are also used in courtship or spawning.

Bluntnose minnows probably release chemicals called pheromones when they are alarmed.

What do they eat?

Bluntnose minnows eat algae, aquatic insect larvae, diatoms, and small crustaceans called entomostracans. Occasionally they will eat fish eggs or small fish.

What eats them and how do they avoid being eaten?

This small fish is prey to many larger fish as well as many birds and reptiles. To avoid predators, minnows move fast, travel in groups called schools, or hide.

Like other minnows, these fish probably release a chemical called "alarm substance" when under attack. Scientists think the substance may be a distress signal that attracts other predatory fish who may interrupt the first predator and allow the minnow to escape.

The list below is only a sample of the species that eat minnows.

What roles do they have in the ecosystem?

Bluntnose minnows serve an important role as prey for larger animals and as a predator on insect larvae

How do they interact with us?

Bluntnose minnows are commonly used for bait in the fishing industry. They are also used as a food source for raising larger sport fish, such as bass.

Are they endangered?

This is a very common fish. In fact, bluntnose minnows are probably the most abundant freshwater fish in the eastern United States.

Contributors

Cynthia Sims Parr, University of Michigan

References

Chivers, D., G. Brown, R. Smith. 1996. Evolution of chemical alarm signals: attracting predators benefits alarm signal senders. American Naturalist, 148: 649-659.

Froese, R., D. Pauly, eds.. 2002. "Fishbase: Pimephales notatus" (On-line). Accessed 27 March 2002 at http://www.fishbase.org.

Johnson, C., D. Johnson. 2000. Sound Production in Pimephales notatus (Rafinesque) (Cyprinidae). Copeia, 2000(2): 567-571.

Page, L., B. Burr. 1991. A field guide to freshwater fishes. Boston: Houghton Mifflin.

State of Iowa DNR, 2001. "Bluntnose minnow card" (On-line). Accessed 27 March 2002 at http://www.state.ia.us/government/dnr/organiza/fwb/fish/iafish/minnow/card/bnm-card.htm.

USGS Great Lakes Science Center, 1982. "Atlas of the Spawning and Nursery Areas of Great Lakes Fishes" (On-line). Accessed 28 March 2002 at http://www.glsc.usgs.gov/information/atlas/volumes/volume13.pdf.