Invasion History

First Non-native North American Tidal Record: 1936
First Non-native West Coast Tidal Record: 1955
First Non-native East/Gulf Coast Tidal Record: 1936

General Invasion History:

Fathead Minnows (Pimephales promelas) are native to much of North America from Quebec to the Northwest Territories, and south to Alabama, Texas, and New Mexico, including the Great Lakes, much of the Arctic, and Mississippi-Gulf drainages (Page and Burr 1991). They were widely introduced a forage fish and through bait-bucket releases in Western and Northeastern drainages (Page and Burr 1991). They have been introduced to drainages outside their native range in 33 states (Fuller et al. 1999), including the Hudson River (Mills et al. 1997) and the San Francisco Bay Delta (Cohen and Carlton 1995). They have also been introduced to Germany, France and Belgium (Lever 1996; Dümpelmann et al. 2015).

North American Invasion History:

Invasion History on the West Coast:

In 1953, a fish breeder received a license to raise Fathead Minnows in Sacramento County. The fish were sold to other breeders for brood stock, and to the state, which stocked them in many lakes as forage fish. The minnow is the main legal baitfish in California. Fathead Minnows were found in the Sacramento-San Joaquin Delta in 1959 (Cohen and Carlton 1995; Dill and Cordone 1997). They are rare to common in channelized streams and dead-end sloughs (Wang 1986; Feyrer and Healy 2003; Leidy 2007) and have been found in fresh-to-brackish Suisun Marsh (Matern et al. 2002). They are widespread in smaller streams in Southern California (Swift et al. 1993) and were collected in the lower reaches and mouth of the Santa Clara River in Ventura County (Bell 1979).

In 2006, a biologist caught two Fathead Minnows in the tidal Willamette River, near its junction with the Columbia River, near Portland, Oregon (USGS Nonindigenous Aquatic Species Program 2018). We do not know of any other records from the Columbia River. However, this fish is widely raised and sold for bait, so it could show up in other estuarine waters.

Invasion History on the East Coast:

Fathead Minnows (Pimephales promelas) were absent in Atlantic drainages south of the St. Lawrence River, but have been introduced to many northeastern streams. Their preferred habitats are muddy pools, small streams, creeks and small rivers (Page and Burr 1991). Occurrences in larger rivers may result from bait releases, or from fish washed downstream by floods. In the Hudson River, Fathead Minnows were first reported from tributaries in 1936 (Mills et al. 1993), and in the river by the 1970s. They do not occur in the main channel of the river, but juveniles and larvae are abundant in the mouths of tributaries (Daniel et al. 2005). In the Delaware River system, Fathead Minnows were first collected in the Schuylkill River near Philadelphia and are were considered possibly established in the tidal parts of the Schuylkill and Delaware in the late 1980s (Horwitz 1986). They were found in the upper Susquehanna drainage in 1936 (Greeley 1939) but were not reported for Pennsylvania by Fowler (1948). By 1970, they were present in Pennsylvania tributaries (Tsai 1971) and in Conowingo Reservoir by 1973 (Denoncourt and Cooper 1975), and below Conowingo Dam, near tidal waters in 1972-1984 (McKeown 1984). Fathead Minnows were rarely seen in the lower Potomac River and its tributaries (Starnes et al. 2011). However, Fathead Minnows have been caught several times in 2006 and 2007 in the Rhode River, a small, brackish tidal tributary (Rob Aguilar, personal communication).

Invasion History Elsewhere in the World:

Fathead Minnows have been widely released in Atlantic and Western drainages in the United States, east and west of their native range. They have been stocked or collected in several streams, ponds, and reservoirs in Puerto Rico from 1957 to 2004 (USGS Nonindigenous Aquatic Species Program 2018). Some of these stockings were for forage for Largemouth Bass, which quickly eliminated them (Lever 1996). Fathead Minnows have also been introduced to England, Belgium, France, and Germany. Small populations in England, of an ornamental 'cherry-rose' variety, were eradicated in 2010 (Britton et al. 2011). In France, Germany, and Belgium, they were raised and sold as bait in 1983, and later for ornamental varieties by the aquarium and fish-pond industry (Lever 1996). Small feral populations have been established from 2001-2012 in France, Belgium, and Germany (Dumpelman and Freyhof 2015).


Fathead Minnows (Pimephales promelas) are small freshwater minnows in the family Cyprinidae. Fish in this family, the carp and minnow family, have a single dorsal fin, abdominal pelvic fins, and a lateral line. They lack true spines in their fins. The fathead minnow has a deep, compressed, chunky body, with the head flattened on top. The snout is blunt, with a terminal, slanted head. The eyes are round. The dorsal fin origin is above the pelvic fin origin. There eight dorsal rays and seven anal rays. The first dorsal ray is short and thick. There are 40-54 lateral line scales. The lateral line fades out towards the tail. Breeding males have a thick, fleshy pad, and about 16 large tubercles, in three rows, on top of their heads. Adults reach 100 mm. The back of the fish is brown or olive, and the sides are dull and dusky, with the black peritoneum often visible as a dark band along the side. Breeding males are dark-brown to black (Page and Burr 1991; Moyle 2002). Orange-gold morphs ('Cherry-Rose') have been bred for the aquarium trade (Dümpelmann et al. 2015).


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Chordata
Subphylum:   Vertebrata
Superclass:   Osteichthyes
Class:   Actinopterygii
Subclass:   Neopterygii
Infraclass:   Teleostei
Superorder:   Ostariophysi
Order:   Cypriniformes
Family:   Leuciscidae
Genus:   Pimephales
Species:   promelas


Potentially Misidentified Species

Pimephales notatus
Pimephales nototatus (Bluntnose Minnow) is slenderer, and has a blunt, but more rounded snout. It is native from the St. Lawrence River, Great Lakes, and Mississippi basin, west to eastern Manitoba and Oklahoma (Page and Burr 1991). Its status in Atlantic basins is variable, and uncertain. It is considered introduced in the Connecticut Housatonic Rivers (Whitworth 1968), native in the Hudson River (Smith and Lake 1990), probably native in the Delaware and Susquehanna, and probably introduced in the Potomac, Rappahannock, and James Rivers. It is also widely sold and used as bait (Jenkins and Burkhead 1993).



Fathead Minnows (Pimephales promelas) are small freshwater fish. Males are larger than females. Breeding males have a blunt snout with large tubercles on the snout and chin, and a large fleshy pad on the nape. Males choose, clean, and guard a nest site, on a leaf, the underside of a rock or shell. The cleaning is done with the pad on the nape, which also spreads mucus to attract the females. Several females may lay small batches of eggs. Total fecundity is 600 to 2300 eggs (Moyle 2002; Dumpelmann and Freyhof 2015). Eggs hatch in about 5 days at 19-25 C. Newly hatched larvae remain on the bottom until the yolk sac is absorbed, and then disperse into shallow water (Wang 1986). Depending on temperature and food, the minnows can mature in less than a year and can live for three years (Jenkins and Burkhead 1993).

Fathead Minnows are a freshwater fish, commonly associated with small, muddy streams, ponds and pools (Page and Burr 1991; Moyle 2002). They tolerate a wide range of temperatures, from 0 to 33 C (Carlander 1969), and low oxygen, high alkalinity, and high turbidity environments. They are freshwater fish, but in experiments, tolerated salinities up to 15 PSU (Nelson 1968). Common habitats include temporary streams, pools, ditches, vegetated shallow waters, and are rare in the deep water of lakes or the main channels (Page and Burr 1991; Jenkins and Burkhead 1993; Moyle 2002). These fish are omnivorous, feeding on algae, small invertebrates, and detritus (Moyle 2002). They are quick to colonize temporary waters, and often are most abundant in habitats where they are the only species (Moyle 2002). Fathead Minnows are rare in highly diverse fish communities and seem to be vulnerable both to predation and competition (Jenkins and Burkhead 1993).


Tolerances and Life History Parameters

Minimum Temperature (ºC)0Carlander 1969
Maximum Temperature (ºC)33Carlander 1969
Minimum Salinity (‰)0This is a freshwater fish.
Maximum Salinity (‰)15 In laboratory experiments at 8 C, P. promelas died at a mean salinity of 21 ppt, when salinity was gradually increased by 3.5 ppt per day. In another experiment at 16 C, the mean salinity was 15 ppt (Nelson 1968).
Maximum pH9.8Jenkins and Burkhead 1994
Minimum Reproductive Temperature15Carlander 1969
Maximum Reproductive Temperature32Carlander 1969
Minimum Length (mm)40Jenkins and Burkhead 1994
Maximum Length (mm)100Page and Burr 1991; common length 73 mm (Froese and Pauly 2018)
Broad Temperature RangeNoneCold temperate-Warm Temperate
Broad Salinity RangeNoneLimnetic-Mesohaline

General Impacts

Fathead Minnows (Pimephales promelas) are unusually tolerant of crowding, low oxygen, high temperatures, turbidity, and survive well in bait buckets, so they are the most widely reared and used baitfish in North America (LoVullo and Stauffer 1883; Killian et al. 2012). They have been stocked as forage fish in hatcheries and reservoirs (Dill and Cordone 1997; Moyle 2002). There is a limited use of ornamental varieties of this minnow in the aquarium and fish pond trade, mostly in Europe (Dumpelman et al. 2015). They have also been used for mosquito control as a substitute for the more invasive Western Mosquitofish (Gambusia affinis) (Watchorn et al. 2018). Fathead Minnows are relatively rare in estuaries and appear to have few impacts in tidal waters. However, they are potential predators and competitors of fishes confined to limited habitats, such as desert springs and streams (Moyle 2002).

Fathead Minnows, introduced to Europe as a baitfish, were a vector of Enteric Redmouth Disease (Yersina ruckeri), infecting cultured salmon and trout (Peeler et al. 2011).

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
M130 Chesapeake Bay 1972 Def Estab
M060 Hudson River/Raritan Bay 1936 Def Estab
M090 Delaware Bay 1966 Def Estab
P090 San Francisco Bay 1955 Def Estab
P260 Columbia River 2006 Def Unk
N090 Kennebec/Androscoggin River 1999 Def Estab
GL-III Lake Ontario 0 Native Estab
GL-II Lake Erie 0 Native Estab
GL-I Lakes Huron, Superior and Michigan 0 Native Estab
LNIPIGON Lake Nipigon 0 Native Estab
LWINNI Lake Winnipeg 0 Native Estab
LMANIT Lake Manitoba 0 Native Estab
LWINNIPOG Lake Winnipogosis 0 Native Estab
REINDEER Reindeer Lake 0 Native Estab
LATHAB Lake Athabasca 0 Native Estab
GSLAVEL Great Slave Lake 0 Native Estab
P064 _CDA_P064 (Ventura) 1975 Def Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


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Cohen, Andrew N.; Carlton, James T. (1995) Nonindigenous aquatic species in a United States estuary: a case study of the biological invasions of the San Francisco Bay and Delta., U.S. Fish and Wildlife Service and National Sea Grant College Program (Connecticut Sea Grant), Washington DC, Silver Spring MD.. Pp. <missing location>

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Feyrer, Frederick; Healey, Michael P. (2003) Fish community structure and environmental correlates in the highly altered southern Sacramento-San Joaquin Delta., Environmental Biology of Fishes 66: 123-132

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Jenkins, Robert E.; Burkhead, Noel M. (1993) Freshwater Fishes of Virginia, American Fisheries Society, Bethesda, MD. Pp. <missing location>

Kilian, Jay V. and 6 authors (2012) An assessment of a bait industry and angler behavior as a vector of invasive species, Biological Invasions 14: published online

Lee, David S.; Gilbert, Carter R.; Hocutt, Charles H.; Jenkins, Robert E.; McAllister, Don E.; Stauffer, Jay R. (1980) Atlas of North American freshwater fishes, North Carolina State Museum of Natural History, Raleigh. Pp. <missing location>

Leidy, R. A. (2007) <missing title>, San Francisco Estuary Institute, Oakland. Pp. <missing location>

Lever, Christopher (1996) Naturalized fishes of the world, Academic Press, London. Pp. <missing location>

Litvak, M. K., Mandrak, N. E. (1993) Ecology of freshwater baitfish use in Canada and the United States, Fisheries 18(12): 6-13

Loos, Jules J., Woolcott, William S., Foster, Neal R. (1972) An ecologist's guide to the minnows of the freshwater drainage systems of the Chesapeake Bay estuary, ASB Bulletin 19(3): 126-138

LoVullo, Thomas J.; Stauffer, Jay R. (1993) The retail bait-fish industry in Pennsyvania- source of introduced species, Journal of the Pennsylvania Academy of Science 67(1): 13-15

Matern, Scott A.; Moyle, Peter; Pierce, Leslie C. (2002) Native and alien fishes in a California estuarine marsh: twenty-one years of changing assemblages, Transactions of the American Fisheries Society 131: 797-816

McKeown, Paul E. (1984) Additions to ichthyofauna of the Susquehanna River with a checklist of fishes of the Susquehanna River drainage below Conowingo Dam, Proceedings of the Pennsylvania Academy of Science 58: 187-192

Mills, Edward L.; Scheuerell, Mark D.; Carlton, James T.; Strayer, David (1997) Biological invasions in the Hudson River: an inventory and historical analysis., New York State Museum Circular 57: 1-51

Musick, J. A.; Wiley, Martin L. (1972) Fishes of Chesapeake Bay and the adjacent coastal plain, Special Scientific Report, Virginia Institute of Marine Science 65: 175-212

Page, Lawrence M.; Burr, Brooks M. (1991) Freshwater Fishes: North America North of Mexico, Houghton-Mifflin, Boston. Pp. <missing location>

Petrocelli, Antonella; Cecere, Ester; Rubino, Fernando (2019) Successions of phytobenthos species in a Mediterranean transitional water system: the importance of long term observations, Nature Conservation 34: 217-246

Raasch, Maynard S. (1996) <missing title>, T.F.H. Publications, Neptune, NJ. Pp. <missing location>

Schwartz, Frank J. (1963) The freshwater minnows of Maryland, Maryland Conservationist 40(2): 19-29

Simon, Carol A.; van Niekerk, H. Helene; Burghardt, Ingo; ten Hove, Harry A.; Kupriyanova, Elena K. (2019) Not out of Africa: Spirobranchus kraussii (Baird, 1865) is not a global fouling and invasive serpulid of Indo-Pacific origin, Biological Invasions 14(3): 221–249.

Smith, C. Lavett, Lake, Thomas R. (1990) Documentation of the Hudson River fish fauna, American Museum Novitates 2981: 1-17

Starnes, Wayne C.; Odenkirk, John; Ashton, Matthew J. (2011) Update and analysis of fish occurrences in the lower Potomac River drainage in the vicinity of Plummers Island, Maryland—Contribution XXXI to the natural history of Plummers Island, Maryland, Proceedings of the Biological Society of Washington 124: 280-309

Swift, Camm C., Haglund, Thomas R., Ruiz, Mario, Fisher, Robert N. (1993) The status and distribution of the freshwater fishes of southern California, Bulletin of the Southern California Academy of Sciences 92(3): 101-167

Tsai,C.-F. (1971) Occurrence of the fathead minnow, Pimephales promelas (Pisces: Cyprinidae), in the Chesapeake Atlantic slope drainages, Chesapeake Science 12(4): 274-275

2003-2015 Nonindigenous Aquatic Species Database. Gainesville, FL.

Waldman, John R.; Lake, Thomas R.; Schmidt, Robert E. (2006) Biodiversity and zoogeography of the fishes of the Hudson River watershed and estuary, American Fisheries Society Symposium 51: 129-150.

Wang, Johnson C. S. (1986) Fishes of the Sacramento - San Joaquin Estuary and Adjacent Waters, California: A Guide to the Early Life Histories, IEP Technical Reports 9: 1-673