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Noturus flavus

What do they look like?

Stonecats are tan to gray dorsally and yellowish to white ventrally. The adipose fin is attached to the back of the stonecat throughout its entire length. The adipose fin is separated from the caudal fin by a notch. The pectoral fin lacks any posterior serrae. Anal fin rays number 15 to 18, pectoral fin rays 9 to 11, and pelvic fin rays 8 to 10. The caudal fin rays number 55 to 67. Stonecats also have a pale margin outlining the caudal fin. They have a premaxillary band of teeth located on the roof of their mouth that has backward extensions. This tooth patch is absent in other species of madtoms. (Eddy and Underhill, 1974; Etnier and Starnes, 1993; Trautman, 1981)

  • Sexual Dimorphism
  • sexes alike
  • female larger
  • Range mass
    .1 to .5 kg
    0.22 to 1.10 lb
  • Range length
    79 to 137 mm
    3.11 to 5.39 in
  • Average length
    114 mm
    4.49 in

Where do they live?

Stonecats (Noturus flavus) are native to the Neartic region. They occur throughout the upper Mississippi Basin, much of the Great Lakes drainage, and in the Hudson Bay drainage in the Red River (Etnier and Starnes, 1993). Their range extends north into some Canadian provinces such as Ontario and Alberta. (Etnier and Starnes, 1993; Hammerson, 2005)

What kind of habitat do they need?

Stonecats live in freshwater environments. They are found in large creeks and small rivers. They occasionally occur in tiny creeks or rivers as large as the lower Mississippi (Etnier and Starnes, 1993). Stonecats occupy gently- to fast-moving riffle areas that have a rocky substrate. Stonecats spend the majority of their time in moderate moving, shallow riffles. They can also be found in deeper water in the 2 to 3 meter range. Stonecats also occur in natural lakes such as Lake Erie. There they prefer rock and gravel bars that are subject to a lot of wave action. (Branson and Batch, 1974; Etnier and Starnes, 1993; Hammerson, 2005; Kline and Morgan, 2000)

  • Aquatic Biomes
  • benthic
  • lakes and ponds
  • rivers and streams
  • Range depth
    .3 to 3 m
    0.98 to 9.84 ft
  • Average depth
    .5 m
    1.64 ft

How do they grow?

In the first year in South Dakota young reached 79 mm. In the third through the fourth years they averaged 99, 114, and 137 mm. (Eddy and Underhill, 1974; Etnier and Starnes, 1993)

How do they reproduce?

Stonecats form monogamous pairs for breeding. (Eddy and Underhill, 1974; Etnier and Starnes, 1993; Hammerson, 2005)

Stonecats spawn when water temperatures reach 25 degree C. The female deposits a jelly like cluster of eggs that number from 100-500 on the underside of flat stones or other, similar structures. The male is thought to guard the nest until the young hatch. Some believe that the female also may play a role in guarding the eggs. The adults will guard the nest until the young are ready to leave. (Eddy and Underhill, 1974; Etnier and Starnes, 1993; Hammerson, 2005)

  • How often does reproduction occur?
    Stonecats breed once yearly.
  • Breeding season
    Stonecats nest from April to July.
  • Range number of offspring
    200 to 1200
  • Average number of offspring
  • Average age at sexual or reproductive maturity (female)
    3 years
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    1095 days
  • Average age at sexual or reproductive maturity (male)
    3 years
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    1095 days

The nest is guarded by what is thought to be the male, but some believe the female also takes part in guarding the young. It is more commonly understood that the male does all or most of the guarding of the young from the time the eggs are laid until the time the eggs hatch. The male continues to guard the fry until they leave the nest. (Etnier and Starnes, 1993; Hammerson, 2005; Trautman, 1981)

How long do they live?

The lifespan of stonecats in captivity is not known. In an Illinois population the lifespan was only 5 to 6 years. The max reported age was 7 years. (Etnier and Starnes, 1993; Page and Burr, 1991)

  • Range lifespan
    Status: wild
    7 (high) years
  • Typical lifespan
    Status: wild
    5 to 6 years
  • Average lifespan
    Status: wild
    5-6 years
  • Typical lifespan
    Status: captivity
    5 to 9 years

How do they behave?

Both adult and juvenile stonecats exhibit nocturnal behavior. They spend their days under rocks and woody structure where it is dark. They come out at night to feed in the shallows. (Hammerson, 2005)

Home Range

No information was present on home range of stonecats. Due to the sedentary behavior of stonecats, it would leave one to believe that their home range would be small in size. (Hammerson, 2005)

How do they communicate with each other?

Stonecats like the other members of the catfish family, have barbels and dermal taste buds that are used for the location of food. Dermal taste buds are located on the edipermis of the fish rather than the mouth. (Etnier and Starnes, 1993; Trautman, 1981)

What do they eat?

Stonecats are primarily invertivores. The young will feed upon the larvae of mayflies (Ephemeroptera), stoneflies (Plecoptera) caddisflies (Trichoptera), and midges (Chironomidae). Adult stonecats will feed on mainly mayfly larvae and crayfish (Astacoidea), but they will also take small darters and minnows. (Etnier and Starnes, 1993; Hammerson, 2005)

  • Animal Foods
  • fish
  • insects
  • aquatic crustaceans

What eats them and how do they avoid being eaten?

The main predators of stonecats are larger freshwater fishes. Humans often catch stonecats and use them as bait for other freshwater species of fish. (Eddy and Underhill, 1974; Etnier and Starnes, 1993; Trautman, 1981)

  • These animal colors help protect them
  • cryptic

What roles do they have in the ecosystem?

Stonecats are neither commensal nor mutualist partners with other species. However they are known to host one mussel species, (Epioblasma obliquata obliquata). (Cummings and Watters, 2004)

Commensal or parasitic species (or larger taxonomic groups) that use this species as a host
  • (Epioblasma oblquata obliquata)

Do they cause problems?

The only problem stonecats may pose for a human is their ability to puncture a person's skin and inflict a painful sting, similar to a wasp. They have a gland at the base of their pectoral and dorsal fins that was thought to secrete a toxin. Recent research shows that the membrane surrounding the spine is responsible for the toxin. The effect of the basal gland is unknown. (; Ohio Department of Natural Resources, 2002; Etnier and Starnes, 1993)

  • Ways that these animals might be a problem for humans
  • injures humans
    • bites or stings

How do they interact with us?

Stonecats serve as indicators of water quality. They are not present in highly polluted areas or areas with a large amount of siltation. Stonecats are a very valuable indicator species to humans. (; Ohio Department of Natural Resources, 2002; Trautman, 1981)

Are they endangered?

The IUCN Red List, CITIES appendices, and the US Endangered Species Act list the status of Noturus flavus as not threatened or no special status, meaning that there is no threat of this species going extinct.

Some more information...

Stonecats are good indicators of smallmouth bass (Micropterus dolomieu) populations. It seems if there is a good population of stonecats in the area, there will also be a good number of smallmouth bass. (Ohio Department of Natural Resources, 2002)


Tanya Dewey (editor), Animal Diversity Web.

Daniel Barrett (author), Eastern Kentucky University, Sherry Harrel (editor, instructor), Eastern Kentucky University.


Branson, B., D. Batch. 1974. Fishes of the Red River Drainage, Eastern Kentucky. Lexington: The University Press of Kentucky.

Cummings, K., G. Watters. 2004. "Mussel Host Database" (On-line). The Ohio State University Division of Molluscs. Accessed November 01, 2005 at

Eddy, S., J. Underhill. 1974. Northern Fishes. Minneapolis: University of Minnesota Press.

Etnier, D., W. Starnes. 1993. The Fishes of Tennessee. Knoxville: The University of Tennessee Press.

Hammerson, G. 2005. "NatureServe Explorer: An online encyclopedia of life." (On-line). NatureServe Explorer. Accessed October 30, 2005 at

Kline, M., R. Morgan. 2000. "Maryland DNR" (On-line). Current Distribution, Abundance, and Habitat Preferences of the Stonecat (Noturus flavus) in Maryland. Accessed November 01, 2005 at

Ohio Department of Natural Resources, 2002. "Stonecat Madtom" (On-line). Accessed October 31, 2005 at

Page, L., B. Burr. 1991. A field guide to freshwater fishes of North America north of Mexico. Boston: Houghton Mifflin Company.

Trautman, M. 1981. The Fishes of Ohio. Columbus: Ohio State University Press.

University of Michigan Museum of ZoologyNational Science Foundation

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Barrett, D. 2006. "Noturus flavus" (On-line), Animal Diversity Web. Accessed March 02, 2024 at

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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