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Pylodictis olivaris

What do they look like?

This is a large catfish that can reach lengths over 1 meter and over 56 kg in weight. Flathead catfish are also called mud catfish because of their yellow to purple-brown dorsal coloration. The belly is pale white to yellow. Not surprisingly, their head is wider and flatter than other North American catfishes. The lower jaw protrudes farther out than the upper jaw, with the mouth having a wide oval shape. The caudal fin has rounded to slightly notched posterior margin and a white tip on the upper lobe (except in large adults), which can be used to distinguish this species from other catfish. Flathead catfish have both pectoral and dorsal-fin spines. The anal fin is short and rounded in profile, and contains 14 to 17 elements. Males and females look alike. (Brown, et al., 2005; Kwak, et al., 2006; Lee and Terrell, 1987; Page and Burr, 2011)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    0.5 to 56.7 kg
    1.10 to 124.89 lb
  • Average mass
    20.4 kg
    44.93 lb
  • Range length
    38.1 to 114.3 cm
    15.00 to 45.00 in

Where do they live?

Flathead catfish are native to rivers and lakes in the lower Great Lakes and Mississippi River basin. They are found in appropriate habitat in Texas, Louisiana, Arkansas, Oklahoma, Arkansas, Missouri, Kansas, much of Nebraska, South Dakota, North Dakota, Iowa, Minnesota, Illinois, Indiana, Ohio, Kentucky, western Virginia, Tennessee, Alabama, and as far south as Mexico. They have been introduced farther east and west of their native range, to parts of Washington, Oregon, California, Arizona, New Mexico, Wyoming, Colorado, Georgia, South Carolina, North Carolina, Virginia, and Pennsylvania. (Fuller and Neilson, 2001; Page and Burr, 2011)

What kind of habitat do they need?

Flathead catfish are found in rivers, lakes, and reservoirs with slow currents. Younger individuals prefer shallower water. Older and larger flathead catfish stay in deeper waters during the daylight hours, moving into shallower water at night. They prefer to stay near or under cover, including fallen trees, logs, brush piles, and river banks. A log that is 5 m long is large enough to provide sufficient cover for one large adult flathead catfish. These catfish are generally found in waters from 21.7 to 30 degrees Celsius. (Brown, et al., 2005; Lee and Terrell, 1987; Malindzak, 2006; Minckley and Deacon, 1959; Page and Burr, 2011)

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams
  • Range depth
    3 to 6 m
    9.84 to 19.69 ft

How do they grow?

Fertilized eggs hatch in 6 to 9 days, depending on temperature. Larvae hatch at 11 to 14.8 mm total length and have a large yolk sac that helps them to complete their development. Like other catfish species, flathead catfish grow continuously, gradually attaining adult body proportions and coloration patterns. (Lee and Terrell, 1987; Simon and Wallus, 2003)

How do they reproduce?

Flathead catfish mating systems have not been observed in the wild, but there is information on mating in captivity. Males court females with body movements until they are ready to release their eggs. At that time, the female deposits eggs in a depression on the bottom of the stream and males fertilize the eggs. Males then defend the eggs as they develop. (Simon and Wallus, 2003)

Flathead catfish become mature at different ages, depending on where they are, but usually between 3 and 7 years old. Spawning occurs in early to late summer, when the water temperature is 23.8 to 29 degrees Celsius, with eggs hatching 6 to 9 days after they are fertilized. Nests for the eggs are found under submerged logs or rocks. Larger females can lay more eggs, a single nest can contain up to 100,000 eggs. The eggs are sticky, so they adhere to the nest when they are released. (Lee and Terrell, 1987; Simon and Wallus, 2003)

  • How often does reproduction occur?
    Flathead catfish breed once yearly
  • Breeding season
    Spawning occurs in June and July.
  • Range number of offspring
    100,000 (high)
  • Range time to hatching
    6 to 9 days
  • Range age at sexual or reproductive maturity (female)
    3 to 7 years
  • Average age at sexual or reproductive maturity (female)
    4 years
  • Range age at sexual or reproductive maturity (male)
    3 to 5 years

Males guard the eggs until they hatch, after which he will continue to protect the newborn fish for several days. (Lee and Terrell, 1987; Simon and Wallus, 2003)

  • Parental Investment
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • male
  • pre-independence
    • protecting
      • male

How long do they live?

Flathead catfish can live up to 28 years, although the typical lifespan is 5 to 22 years. Due to the large size of adults, this species is not commonly kept in captivity. (Kwak, et al., 2006)

  • Range lifespan
    Status: wild
    28 (high) years
  • Typical lifespan
    Status: wild
    5 to 22 years

How do they behave?

Flathead catfish are found in deeper parts of rivers and lakes. They are ambush predators, waiting under cover for their prey to cross their path. They are mainly nocturnal, but are sometimes active during the day as well. Flathead catfish eat mainly fish, including other large fish. They stop being active when water temperatures drop below 10°C. (Brown, et al., 2005; Daugherty and Sutton, 2005; Eggleton and Schramm, 2004; Lee and Terrell, 1987)

  • Range territory size
    0 to 3601 m^2
  • Average territory size
    1135 m^2

Home Range

Home range sizes of flathead catfish change throughout the year, they generally have larger home ranges during the warm months than during cold months. (Daugherty and Sutton, 2005)

How do they communicate with each other?

Flathead catfish use touch and taste to communicate during spawning. They use their eyes, lateral line system, and taste receptors that are concentrated on their barbels (whiskers). They have an improved sense of hearing because the swim bladder serves as a resonance chamber and is connected to the inner ear. (Hoagland, 1933; Kanwal and Caprio, 1987; Nelson, 2006; Pohlmann, et al., 2004)

What do they eat?

Flathead catfish are carnivores that prey on many different types of animals, depending on their size. They eat crayfish, gizzard shad, insects and larvae, channel catfish, drum, other flathead catfish, green sunfish, and carp. Insect larvae are the major prey type until an individual reaches approximately 100 mm in total length, at which point the diet expands to include crayfish and small fishes. Individuals above 250 mm in length feed almost exclusively on other fish. (Brown, et al., 2005; Layher and Boles, 1980; Simon and Wallus, 2003)

  • Animal Foods
  • fish
  • insects
  • aquatic crustaceans

What eats them and how do they avoid being eaten?

Flathead catfish have no known predators other than members of their own species and humans who fish for them. Although, when they are larvae and younger, smaller fish, they are likely to be prey to other fish, wading birds, such as herons, and other medium-sized predators that forage in rivers and streams. (Brown, et al., 2005)

  • These animal colors help protect them
  • cryptic

What roles do they have in the ecosystem?

Flathead catfish are one of the top predators of other fishes in the areas they are found. They hostover 25 different parasite species, including several types of flatworms, nematodes, spiny-headed worms, leeches, copepods, water lice, and freshwater mussel larvae. (Brown, et al., 2005; Causey, 1957; Hoffman, 1999; Poly, 1997; Robinson and Jahn, 1980)

Commensal or parasitic species (or larger taxonomic groups) that use this species as a host
  • Ambiphrya ictaluri (Order Ciliata, Phylum Ciliophora)
  • Ligictaluridus floridanus (Class Monogenea, Phylum Platyhelminthes)
  • Ligictaluridus mirabilis (Class Monogenea, Phylum Platyhelminthes)
  • Allochanthochasmus artus (Class Trematoda, Phylum Platyhelminthes)
  • Alloglossidium corti (Class Trematoda, Phylum Platyhelminthes)
  • Caecincola parvulus (Class Trematoda, Phylum Platyhelminthes)
  • Crepidostomum cornutum (Class Trematoda, Phylum Platyhelminthes)
  • Phyllodistomum lacustri (Class Trematoda, Phylum Platyhelminthes)
  • Phyllodistomum staffordi (Class Trematoda, Phylum Platyhelminthes)
  • Podocotyle boleosomi (Class Trematoda, Phylum Platyhelminthes)
  • Corallobothrium fimbriatum (Class Cestoda, Phylum Platyhelminthes))
  • Corallobothrium giganteum (Class Cestoda, Phylum Platyhelminthes))
  • Corallobothrium tva (Class Cestoda, Phylum Platyhelminthes))
  • Marsipometra sp. (Class Cestoda, Phylum Platyhelminthes)
  • Proteocephalus ambloplitis (Class Cestoda, Phylum Platyhelminthes)
  • Proteocephalus macrocephalus (Class Cestoda, Phylum Platyhelminthes)
  • Camallanus oxycephalus (Class Secernentea, Phylum Nematoda)
  • Contracaecum spiculigerum (Class Secernentea, Phylum Nematoda)
  • Dacnitoides sp. (Class Secernentea, Phylum Nematoda)
  • Leptorhynchoides thecatus (Class Metacanthocephala, Phylum Acanthocephala)
  • Chloromyxum opladeli (Class Myxosporea, Phylum Cnidaria)
  • Cystobranchus verrilli (Subclass Hirudinea, Phylum Annelida)
  • larvae of unionid mollusks (Unionidae)
  • Actheres pimelodi (Subclass Copepoda, Subphylum Crustacea)
  • Ergasilus versicolor (Subclass Copepoda, Subphylum Crustacea)
  • Argulus appendiculosus (Subclass Branchiura, Subphylum Crustacea)
  • Argulus flavescens (Subclass Branchiura, Subphylum Crustacea)

Do they cause problems?

There are no known negative economic effects of flathead catfish on humans. The fin spines of smaller specimens are quite sharp, and may injure unwary fishermen. (Brown, et al., 2005)

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

How do they interact with us?

Flathead catfish are prized by anglers, and may therefore have positive impacts in terms of ecotourism. (Page and Burr, 2011)

  • Ways that people benefit from these animals:
  • ecotourism

Are they endangered?

There are no current conservation efforts to protect flathead catfish, as they are not considered vulnerable or threatened in any portion of their geographical range.


Nicholas Brodd (author), Radford University, Karen Powers (editor), Radford University, Kiersten Newtoff (editor), Radford University, Melissa Whistleman (editor), Radford University, Jeremy Wright (editor), University of Michigan-Ann Arbor.


Bourret, S., R. Tingley III, Y. Kanno, J. Vokoun. 2008. Maximum daily consumption and specific daily metabolic demand of juvenile flathead catfish (Pylodictis olivaris). Journal of Freshwater Ecology, 23/3: 413-419.

Bringolf, R., T. Kwak, G. Cope, M. Larimore. 2005. Salinity tolerance of flathead catfish: Implications for dispersal of introduced populations. Transactions of the American Fisheries Society, 134/4: 927-936.

Brown, J., J. Perillo, T. Kwak, R. Horwitz. 2005. Implications of Pylodictis olivaris (flathead catfish) introduction into the Delaware and Susquehanna drainages. Northeastern Naturalist, 12/4: 473-484.

Causey, D. 1957. Parasitic copepoda from Louisiana fresh water fish. American Midland Naturalist, 58/2: 378-382.

Daugherty, D., T. Sutton. 2005. Seaonal movement patterns, habit use, and home range of flathead catfish in the lower St. Joseph River, Michigan. North American Journal of Fisheries Management, 25: 256-269.

Eggleton, M., H. Schramm. 2004. Feeding ecology and energetic relationships with habitat of blue catfish, Ictalurus furcatus, and flathead catfish, Pylodictis olivaris, in the lower Mississippi River, U.S.A. Environmental Biology of Fishes, 70/2: 107-121.

Fuller, P., M. Neilson. 2001. "Pylodictis olivaris" (On-line). USGS nonindigenous aquatic species database. Accessed February 09, 2012 at

Hoagland, H. 1933. Specific nerve impulses from gustatory and tackle receptors in catfish. The Journal of General Physiology, 16/4: 685-693.

Hoffman, G. 1999. Parasites of North American Freshwater Fishes. Ithaca, NY: Comstock Publishing Associates (Cornell University Press).

Kanwal, J., J. Caprio. 1987. Overlapping taste and tactile maps of the oropharynx in the vagal lobe of the channel catfish, Ictalurus punctatus. Journal of neurobiology, 19/3: 211-222.

Kwak, T., W. Pine III, S. Waters. 2006. Age, growth, and mortality of introduced flathead catfish in Atlantic rivers and a review of other populations. North American Journal of Fisheries Management, 26: 73-87.

Layher, W., R. Boles. 1980. Food habits of the flathead catfish, Pylodictis olivaris (Rafinesque), in relation to length and season in a large Kansas reservoir. Transactions of the Kansas Academy of Sciences, 83/4: 200-214.

Lee, L., J. Terrell. 1987. Habitat suitability index models: flathead catfish. Fort Collins, CO: U.S. Fish and Wildlife Service.

Malindzak, E. 2006. "Behavior and habitat use of introduced flathead catfish in a North Carolina piedmont river" (On-line). Thesis for North Caroline State University. Accessed February 08, 2012 at

Minckley, W., J. Deacon. 1959. Biology of the flathead catfish in Kansas. Transactons of the American Fisheries Society, 88/4: 344-355.

Nelson, J. 2006. Fishes of the World, Fourth Edition. Hoboken, NJ: John Wiley & Sons, Inc..

Page, L., B. Burr. 2011. A Field Guide to Freshwater Fishes of North America North of Mexico, Second Edition. New York, NY: Houghton Mifflin Harcourt.

Pohlmann, K., J. Atema, T. Breithaupt. 2004. The importance of the lateral line in nocturnal predation of piscivorous catfish. Journal of Experimental Biology, 207: 2971-2978.

Poly, W. 1997. Host and Locality Records of the Fish Ectoparasite, Argulus (Branchiura), from Ohio (U.S.A.). Crustaceana, 70/8: 867-874.

Robinson, G., L. Jahn. 1980. Some observations of fish parasites in pool 20, Mississippi River. Transactions of the American Microscopical Society, 99/2: 206-212.

Simon, T., R. Wallus. 2003. Reproductive Biology and Early Life History of Fishes in the Ohio River Drainage, Volume 3, Ictaluridae-Catfish and Madtoms. Boca Raton, FL: CRC Press LLC.

Vokoun, J., C. Rabeni. 2006. Summer diel activity and movement paths of flathead catfish (Pylodictis olivaris) in two Missouri streams. American Midland Naturalist, 155/1: 113-122.

University of Michigan Museum of ZoologyNational Science Foundation

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Brodd, N. 2012. "Pylodictis olivaris" (On-line), Animal Diversity Web. Accessed October 20, 2017 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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