Gambusia affinis - (Baird and Girard, 1853)
Western Mosquitofish
Other English Common Names: western mosquitofish
Taxonomic Status: Accepted
Related ITIS Name(s): Gambusia affinis (Baird and Girard, 1853) (TSN 165878)
Unique Identifier: ELEMENT_GLOBAL.2.103578
Element Code: AFCNC02010
Informal Taxonomy: Animals, Vertebrates - Fishes - Bony Fishes - Other Bony Fishes
Kingdom Phylum Class Order Family Genus
Animalia Craniata Actinopterygii Cyprinodontiformes Poeciliidae Gambusia
Genus Size: D - Medium to large genus (21+ species)
Check this box to expand all report sections:
Concept Reference
Concept Reference: Robins, C.R., R.M. Bailey, C.E. Bond, J.R. Brooker, E.A. Lachner, R.N. Lea, and W.B. Scott. 1991. Common and scientific names of fishes from the United States and Canada. American Fisheries Society, Special Publication 20. 183 pp.
Concept Reference Code: B91ROB01NAUS
Name Used in Concept Reference: Gambusia affinis
Taxonomic Comments: Gambusia holbrooki from east of the Mobile River formerly was regarded as a subspecies of G. affinis; holbrooki was elevated to full species status by Wooten et al. (1988); this change was adopted in the 1991 AFS checklist (Robins et al. 1991). Page and Burr (1991) retained holbrooki as a subspecies of affinis, noting intergradation in the Mobile Bay basin. Gambusia affinis apparently hybridizes/intergrades with G. holbrooki in some sites in the Chattahoochee and Savannah river drainages (Lydeard et al. 1991).

Member of subgenus Arthrophallus, affinis species group (Rauchenberger 1989). See Rauchenberger (1989) for a study of the interrelationships of the subgenera and species groups within the genus Gambusia. Some southwestern populations of G. affinis were regarded as a distinct species, G. specioisa, by Rauchenberger (1989); Robins et al. (1991) viewed them as, at most, a subspecies of affinis.
Conservation Status

NatureServe Status

Global Status: G5
Global Status Last Reviewed: 03Feb2012
Global Status Last Changed: 20Sep1996
Ranking Methodology Used: Ranked by inspection
Rounded Global Status: G5 - Secure
Nation: United States
National Status: N5 (05Dec1996)
Nation: Canada
National Status: NNA (22Dec2017)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Alabama (S5), Arizona (SNA), Arkansas (S5), California (SNA), Colorado (SNA), Florida (SNR), Georgia (SNR), Idaho (SNA), Illinois (S4S5), Indiana (S5), Iowa (SNA), Kansas (SNA), Kentucky (S4S5), Louisiana (S5), Michigan (SNA), Mississippi (S5), Missouri (SNR), Montana (SNA), Navajo Nation (SNA), Nebraska (SNA), Nevada (SNA), New Jersey (SNA), New Mexico (SNA), North Carolina (SNA), Oklahoma (S5), Oregon (SNA), Tennessee (S5), Texas (S5), Utah (SNA), Washington (SNA), Wisconsin (SNA), Wyoming (SNA)
Canada Alberta (SNA), Ontario (SNA)

Other Statuses

IUCN Red List Category: LC - Least concern

NatureServe Global Conservation Status Factors

Range Extent: 200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Range Extent Comments: This species is native to most of south-central United States, north to Indiana and Illinois, west to Texas, south to southern Mexico, east to Mobile River system. Populations in the drainages of the Chattahoochee and Savannah rivers (Lydeard and Wooten 1991) possibly are native (Page and Burr 2011). See Walters and Freeman (2000) for information on the distribution of G. affinis and G. holbrooki in the Conasauga River system, where G. affinisi is widespread and native and G. holbrooki is apparently introduced and expanding its range. This fish is widely introduced in the western United States and throughout the world.

Lynch (1992) reported that five or six populations from Georgia, Illinois, Tennessee and Texas were used for most introductions nationwide and worldwide. Within the United States, sources from Illinois, Tennessee and Texas were used to establish mosquitofish in the western half of the country. Therefore, most if not all populations in the western United States are G. affinis.

Number of Occurrences: > 300
Number of Occurrences Comments: This species is represented by a large number of occurrences (subpopulations).

Population Size: >1,000,000 individuals
Population Size Comments: "Possibly the single most abundant freshwater fish in the world" (Minckley et al. 1991).

Overall Threat Impact Comments: No major threats are known.

Short-term Trend: Relatively Stable (<=10% change)
Short-term Trend Comments: Trend over the past 10 years or three generations is uncertain but likely relatively stable.

Long-term Trend: Increase of >25%

Other NatureServe Conservation Status Information

Global Range: (200,000-2,500,000 square km (about 80,000-1,000,000 square miles)) This species is native to most of south-central United States, north to Indiana and Illinois, west to Texas, south to southern Mexico, east to Mobile River system. Populations in the drainages of the Chattahoochee and Savannah rivers (Lydeard and Wooten 1991) possibly are native (Page and Burr 2011). See Walters and Freeman (2000) for information on the distribution of G. affinis and G. holbrooki in the Conasauga River system, where G. affinisi is widespread and native and G. holbrooki is apparently introduced and expanding its range. This fish is widely introduced in the western United States and throughout the world.

Lynch (1992) reported that five or six populations from Georgia, Illinois, Tennessee and Texas were used for most introductions nationwide and worldwide. Within the United States, sources from Illinois, Tennessee and Texas were used to establish mosquitofish in the western half of the country. Therefore, most if not all populations in the western United States are G. affinis.

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map
Endemism: occurs (regularly, as a native taxon) in multiple nations

U.S. & Canada State/Province Distribution
United States AL, AR, AZexotic, CAexotic, COexotic, FL, GA, IAexotic, IDexotic, IL, IN, KSexotic, KY, LA, MIexotic, MO, MS, MTexotic, NCexotic, NEexotic, NJexotic, NMexotic, NNexotic, NVexotic, OK, ORexotic, TN, TX, UTexotic, WAexotic, WIexotic, WYexotic
Canada ABexotic, ONexotic

Range Map
No map available.

U.S. Distribution by County Help
State County Name (FIPS Code)
NE Adams (31001), Garden (31069), Jefferson (31095), Keith (31101), Lincoln (31111), Morrill (31123), Thomas (31171)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
03 Middle Chattahoochee-Lake Harding (03130002), Middle Chattahoochee-Walter F. George Reservoir (03130003), Lower Chattahoochee (03130004), Chipola (03130012), Yellow (03140103), Blackwater (03140104), Perdido (03140106), Perdido Bay (03140107), Upper Choctawhatchee (03140201), Pea (03140202), Lower Choctawhatchee (03140203), Upper Conecuh (03140301), Patsaliga (03140302), Sepulga (03140303), Lower Conecuh (03140304), Escambia (03140305), Conasauga (03150101), Upper Coosa (03150105), Middle Coosa (03150106), Lower Coosa (03150107), Upper Tallapoosa (03150108), Middle Tallapoosa (03150109), Lower Tallapoosa (03150110), Upper Alabama (03150201), Cahaba (03150202), Middle Alabama (03150203), Lower Alabama (03150204), Upper Tombigbee (03160101), Town (03160102), Buttahatchee (03160103), Tibbee (03160104), Luxapallila (03160105), Middle Tombigbee-Lubbub (03160106), Sipsey (03160107), Noxubee (03160108), Mulberry (03160109), Sipsey Fork (03160110), Locust (03160111), Upper Black Warrior (03160112), Lower Black Warrior (03160113), Middle Tombigbee-Chickasaw (03160201), Sucarnoochee (03160202), Lower Tambigbee (03160203), Mobile - Tensaw (03160204), Mobile Bay (03160205), Chunky-Okatibbee (03170001), Upper Chickasawhay (03170002), Lower Chickasawhay (03170003), Upper Leaf (03170004), Lower Leaf (03170005), Pascagoula (03170006), Black (03170007), Escatawpa (03170008), Mississippi Coastal (03170009), Upper Pearl (03180001), Middle Pearl-Strong (03180002), Middle Pearl-Silver (03180003), Lower Pearl. Mississippi (03180004), Bogue Chitto (03180005)
05 Little Scioto-Tygarts (05090103), Licking (05100101), South Fork Licking (05100102), Lower Kentucky (05100205), Upper Green (05110001), Barren (05110002), Middle Green (05110003), Rough (05110004), Lower Green (05110005), Pond (05110006), Middle Wabash-Little Vermilion (05120108), Middle Wabash-Busseron (05120111)*, Embarras (05120112), Lower Wabash (05120113), Little Wabash (05120114), Skillet (05120115), Lower White (05120202), Patoka (05120209), Upper Cumberland (05130101), Upper Cumberland-Lake Cumberland (05130103), Upper Cumberland-Cordell Hull (05130106), Collins (05130107), Caney (05130108), Lower Cumberland-Old Hickory Lake (05130201), Lower Cumberland-Sycamore (05130202), Stones (05130203), Harpeth (05130204), Lower Cumberland (05130205), Red (05130206), Silver-Little Kentucky (05140101), Rolling Fork (05140103), Lower Ohio-Little Pigeon (05140201), Highland-Pigeon (05140202), Lower Ohio-Bay (05140203), Saline (05140204), Tradewater (05140205), Lower Ohio (05140206)
06 Holston (06010104), Lower French Broad (06010107), Nolichucky (06010108), Watts Bar Lake (06010201), Lower Little Tennessee (06010204), Lower Clinch (06010207), Emory (06010208), Middle Tennessee-Chickamauga (06020001), Hiwassee (06020002), Ocoee (06020003), Sequatchie (06020004), Guntersville Lake (06030001), Wheeler Lake (06030002), Upper Elk (06030003), Lower Elk (06030004), Pickwick Lake (06030005), Bear (06030006), Lower Tennessee-Beech (06040001), Upper Duck (06040002), Lower Duck (06040003), Buffalo (06040004), Kentucky Lake (06040005), Lower Tennessee (06040006)
07 Green (07090007), Bear-Wyaconda (07110001), North Fabius (07110002), South Fabius (07110003), The Sny (07110004), South Fork Salt (07110006), Salt (07110007), Cuivre (07110008), Peruque-Piasa (07110009), Kankakee (07120001), Chicago (07120003), Des Plaines (07120004), Upper Illinois (07120005), Lower Illinois-Senachwine Lake (07130001), Lower Illinois-Lake Chautauqua (07130003), Lower Sangamon (07130008), Salt (07130009)*, Lower Illinois (07130011), Cahokia-Joachim (07140101), Meramec (07140102), Bourbeuse (07140103), Upper Mississippi-Cape Girardeau (07140105), Big Muddy (07140106), Whitewater (07140107), Cache (07140108), Middle Kaskaskia (07140202)*, Shoal (07140203), Lower Kaskaskia (07140204)
08 Lower Mississippi-Memphis (08010100), Bayou De Chien-Mayfield (08010201), Obion (08010202), South Fork Obion (08010203), North Fork Forked Deer (08010204), South Fork Forked Deer (08010205), Forked Deer (08010206), Upper Hatchie (08010207), Lower Hatchie (08010208), Loosahatchie (08010209), Wolf (08010210), Horn Lake-Nonconnah (08010211)*, Lower Mississippi-Helena (08020100), New Madrid-St. Johns (08020201), Upper St. Francis (08020202), Lower St. Francis (08020203), Little River Ditches (08020204), L'anguille (08020205), Lower White-Bayou Des Arc (08020301), Cache (08020302), Lower White (08020303), Big (08020304), Lower Arkansas (08020401), Bayou Meto (08020402), Lower Mississippi-Greenville (08030100), Little Tallahatchie (08030201), Tallahatchie (08030202), Yocona (08030203), Coldwater (08030204), Yalobusha (08030205), Upper Yazoo (08030206), Big Sunflower (08030207), Lower Yazoo (08030208), Deer-Steele (08030209), Ouachita Headwaters (08040101), Upper Ouachita (08040102), Little Missouri (08040103), Lower Ouachita-Smackover (08040201), Lower Ouachita-Bayou De Loutre (08040202), Upper Saline (08040203), Lower Saline (08040204), Bayou Bartholomew (08040205), Bayou D'arbonne (08040206), Lower Ouachita (08040207), Lower Red (08040301), Castor (08040302), Dugdemona (08040303), Little (08040304), Black (08040305), Bayou Cocodrie (08040306), Boeuf (08050001), Bayou Macon (08050002), Tensas (08050003), Lower Mississippi-Natchez (08060100), Upper Big Black (08060201), Lower Big Black (08060202), Bayou Pierre (08060203), Coles Creek (08060204), Homochitto (08060205), Buffalo (08060206), Lower Mississippi-Baton Rouge (08070100), Bayou Sara-Thompson (08070201), Amite (08070202), Tickfaw (08070203), Lake Maurepas (08070204), Tangipahoa (08070205), Lower Grand (08070300), Atchafalaya (08080101), Bayou Teche (08080102), Vermilion (08080103), Mermentau Headwaters (08080201), Mermentau (08080202), Upper Calcasieu (08080203), Whisky Chitto (08080204), West Fork Calcasieu (08080205), Lower Calcasieu (08080206), Lower Mississippi-New Orleans (08090100), Liberty Bayou-Tchefuncta (08090201), Eastern Louisiana Coastal (08090203), East Central Louisiana Coastal (08090301), West Central Louisiana Coastal (08090302)
10 Middle North Platte-Scotts Bluff (10180009)+, Lower North Platte (10180014)+, Lower South Platte (10190018)+, Dismal (10210002)+, Independence-Sugar (10240011), Platte (10240012), Upper Little Blue (10270206)+, Upper Grand (10280101), Lower Chariton (10280202), Little Chariton (10280203), Lower Marais Des Cygnes (10290102), Little Osage (10290103), Marmaton (10290104), Harry S. Missouri (10290105), Pomme De Terre (10290107), South Grand (10290108), Lower Osage (10290111), Upper Gasconade (10290201), Big Piney (10290202), Lower Gasconade (10290203), Lower Missouri-Crooked (10300101), Lower Missouri-Moreau (10300102), Lamine (10300103), Lower Missouri (10300200)
11 Beaver Reservoir (11010001), Bull Shoals Lake (11010003), Middle White (11010004), North Fork White (11010006), Upper Black (11010007), Current (11010008), Lower Black (11010009), Spring (11010010), Strawberry (11010012), Upper White-Village (11010013), Little Red (11010014), Middle Arkansas-Lake Mckinney (11030001), Coon-Pickerel (11030004), Rattlesnake (11030009), Gar-Peace (11030010), Middle Arkansas-Slate (11030013), North Fork Ninnescah (11030014), South Fork Ninnescah (11030015), Ninnescah (11030016), Upper Walnut River (11030017), Lower Walnut River (11030018), Upper Cimarron (11040002), Upper Cimarron-Liberal (11040006), Crooked (11040007), Upper Cimarron-Bluff (11040008), Lower Cimarron-Eagle Chief (11050001), Lower Cimarron-Skeleton (11050002), Lower Cimarron (11050003), Kaw Lake (11060001), Upper Salt Fork Arkansas (11060002), Medicine Lodge (11060003), Lower Salt Fork Arkansas (11060004), Chikaskia (11060005), Black Bear-Red Rock (11060006), Upper Verdigris (11070101), Fall (11070102), Middle Verdigris (11070103), Elk (11070104), Lower Verdigris (11070105), Caney (11070106), Bird (11070107), Neosho headwaters (11070201), Upper Neosho (11070204), Middle Neosho (11070205), Lake O' the Cherokees (11070206), Spring (11070207), Elk (11070208), Lower Neosho (11070209), Upper Canadian-Ute Reservoir (11080006), Lower Canadian-Deer (11090201), Lower Canadian-Walnut (11090202), Little (11090203), Lower Canadian (11090204), Upper Beaver (11100101), Middle Beaver (11100102), Coldwater (11100103), Palo Duro (11100104), Lower Beaver (11100201), Middle North Canadian (11100301), Lower North Canadian (11100302), Deep Fork (11100303), Polecat-Snake (11110101), Dirty-Greenleaf (11110102), Illinois (11110103), Robert S. Kerr Reservoir (11110104), Poteau (11110105), Frog-Mulberry (11110201), Dardanelle Reservoir (11110202), Lake Conway-Point Remove (11110203), Petit Jean (11110204), Cadron (11110205), Fourche La Fave (11110206), Lower Arkansas-Maumelle (11110207), Lower Salt Fork Red (11120202), Middle North Fork Red (11120302), Lower North Fork Red (11120303), Elm Fork Red (11120304), Groesbeck-Sandy (11130101), Blue-China (11130102), Farmers-Mud (11130201), Cache (11130202), West Cache (11130203), Northern Beaver (11130208), Lake Texoma (11130210), Washita headwaters (11130301), Upper Washita (11130302), Middle Washita (11130303), Lower Washita (11130304), Bois D'arc-Island (11140101), Blue (11140102), Muddy Boggy (11140103), Clear Boggy (11140104), Kiamichi (11140105), Pecan-Waterhole (11140106), Upper Little (11140107), Mountain Fork (11140108), Lower Little (11140109), Mckinney-Posten Bayous (11140201), Middle Red-Coushatta (11140202), Loggy Bayou (11140203), Red Chute (11140204), Bodcau Bayou (11140205), Bayou Pierre (11140206), Lower Red-Lake Iatt (11140207), Saline Bayou (11140208), Black Lake Bayou (11140209), Lower Sulphur (11140302), Cross Bayou (11140304)
12 Toledo Bend Reservoir (12010004), Lower Sabine (12010005), Upper Neches (12020001), Middle Neches (12020002), Upper Angelina (12020004), Lower Angelina (12020005), Upper West Fork Trinity (12030101), Lower West Fork Trinity (12030102), Elm Fork Trinity (12030103), Denton (12030104), Sabine Lake (12040201), Lower Brazos-Little Brazos (12070101), Navasota (12070103), Lower Colorado-Cummins (12090301), Upper Guadalupe (12100201), Middle Guadalupe (12100202), San Marcos (12100203), Lower Guadalupe (12100204), Upper San Antonio (12100301), Medina (12100302), Lower San Antonio (12100303), Cibolo (12100304), Upper Frio (12110106), Hondo (12110107), Lower Frio (12110108), San Miguel (12110109), Atascosa (12110110), Lower Nueces (12110111), South Laguna Madre (12110208)
13 Upper Rio Grande (13020101), Rio Grande-Santa Fe (13020201), Jemez (13020202)*, Rio Grande-Albuquerque (13020203), Elephant Butte Reservoir (13020211), Caballo (13030101)*, El Paso-Las Cruces (13030102), Rio Grande-Fort Quitman (13040100), Cibolo-Red Light (13040201), Black Hills-Fresno (13040203), Big Bend (13040205), Reagan-Sanderson (13040208), Amistad Reservoir (13040212), Pecos headwaters (13060001), Upper Pecos (13060003), Taiban (13060004), Upper Pecos-Long Arroyo (13060007), Upper Pecos-Black (13060011), Lower Pecos-Red Bluff Reservoir (13070001), Delaware (13070002), Lower Pecos (13070008), Elm-Sycamore (13080001), San Ambrosia-Santa Isabel (13080002), International Falcon Reservoir (13080003), Los Olmos (13090001), Lower Rio Grande (13090002)
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
U.S. Distribution by Watershed (based on multiple information sources) Help
Ecology & Life History
Diagnostic Characteristics: G. holbrooki usually has seven dorsal rays and a gonopodium with prominent teeth on ray three. G. affinis usually has six dorsal rays and lacks prominent teeth on gonopodial ray three. Both subspecies have a chromosome number of 2n = 48 but female G. affinis possess a large heteromorphic sex chromosome which is lacking in G. holbrooki (Black and Howell 1979).

In Arizona, G. affinis may be confused with Poeciliopsis occidentalis, the Sonoran topminnow. In topminnows the gonopodium is asymmetrical to the left, large hooks and serrae absent on gonopodial tip, and the gonopodium reaches beyond the snout when directed forward. The pelvic fins of males are unmodified and somewhat reduced. Many breeding males will be blackened. In G. affinis the gonopodium is symmetrical with large hooks and serrae on the tip. The pelvic fins of males are modified with a fleshy appendage on the distal third of the first, short, unbranched ray. Males are rarely blackened.

Reproduction Comments: Fish born early in the spring may reproduce later in the summer and fall. Those born late in the reproductive season overwinter before reproducing (Krumholz 1948). In southcentral Texas, young may be collected from March to October with a peak in abundance in April (Davis 1978). In some constant temperature springs, these fish cease reproduction in winter (Brown and Fox 1966, Davis 1978). However, some populations from thermal habitats (such as cooling ponds and lakes) reproduce year-round (Ferens and Murphy 1974, Bennett and Goodyear 1978). At the Savannah River Power Plant site, South Carolina, fish reproduce throughout the winter although at much reduced brood sizes (Meffe, pers. comm., cited in Constantz 1989). These same workers found that the percentage of reproductively active females increased with increasing water temperature.

Mosquitofish have internal fertilization and are ovoviviparous (Sublette et al. 1990). Females can store sperm from one copulation and fertilize several broods sequentially (Krumholz 1948). After a gestational period of 21 to 28 days, the young are born alive at a size of approximately eight to nine mm total length (Krumholz 1948). Larger females produce more offspring (Krumholz 1948). Brood sizes of one to 315 young have been reported (Barney and Anson 1921, Moyle 1976). Females annually have four to five broods (Krumholz 1948). Sex ratios are 1:1 at birth, but in older cohorts, the number of males declines relative to the number of females (Krumholz 1948). Under optimal conditions females can become gravid at 6 weeks of age, produce 2-3 broods in first summer. Few individuals live more than 15 months (Moyle 1976).

Life history is flexible, varies with environmental conditions (Stearns 1983).

Ecology Comments: May experience severe winter mortality in some areas, but may quickly reestablish population.

Predators include water snakes (Nerodia) (Mushinsky and Hebrard 1977, Kofron 1978), water birds (Kushlan 1973), spiders (Suhr and Davis 1974), and fishes such as black basses and gars (Hunt 1953).

Habitat Type: Freshwater
Non-Migrant: Y
Locally Migrant: N
Long Distance Migrant: N
Estuarine Habitat(s): Bay/sound, Herbaceous wetland, Lagoon, River mouth/tidal river, Tidal flat/shore
Riverine Habitat(s): BIG RIVER, CREEK, Low gradient, MEDIUM RIVER, Pool, SPRING/SPRING BROOK
Lacustrine Habitat(s): Shallow water
Habitat Comments: Habitat includes river channels, margins, backwaters; springs, marshes, and artificial habitats of all kinds (Minckley et al. 1991). Often this species occurs in shallow, often stagnant, ponds and the shallow edges of lakes and streams where predatory fishes are largely absent and temperatures are high. It is most abundant in shallow water with thick vegetation (Hubbs 1971). It also occurs in brackish sloughs and coastal saltwater habitats (Tabb and Manning 1961, Odum 1971). This fish is more tolerant of pollution than are most other fishes (Lewis 1970, Kushlan 1974). It tolerates dissolved oxygen levels as low as 0.18 mg/L (Ahuja 1964) but cannot tolerate extreme cold; temperature apparently limits the range northward (Hubbs 1971). However, some populations are known to overwinter under ice in Indiana and Illinois (Krumholz 1944).
Adult Food Habits: Herbivore, Invertivore
Immature Food Habits: Herbivore, Invertivore
Food Comments: Opportunistic omnivore; eats mainly small invertebrates, often taken near water surface. Also eats small fishes and, in the absence of abundant animal food, algae and diatoms (Moyle 1976).

Mosquitofish are principally carnivorous, and have strong, conical teeth and short guts (Meffe et al. 1983, Turner and Snelson 1984). They are reported to feed on rotifers, snails, spiders, insect larvae, crustaceans, algae, and fish fry, including their own progeny (Barnickol 1941, Minckley 1973, Meffe and Crump 1987). Cannibalism has been documented by several authors (Seale 1917, Krumholz 1948, Walters and Legner 1980, Harrington and Harrington 1982). Plant material is taken occasionally (Barnickol 1941) and may make up a significant portion of the diet during periods of scarcity of animal prey (Harrington and Harrington 1982). Grubb (1972) showed that anuran eggs from temporary ponds were preferentially selected over those breeding in permanent systems. Several workers have documented changes in the prey community after mosquitofish introduction (Hurlbert et al. 1972, Farley and Younce 1977, Hurlbert and Mulla 1981, Walters and Legner 1980).

Due to their name, these fishes are popularly believed to be "super" mosquito-larvae predators. Reddy and Shakuntala (1979), however, found that adult females grew poorly on a diet of mosquito larvae, but they grew quickly on tubifex worms. These results matched the outcome of preference tests, i.e. worms were chosen over mosquito larvae. Cech et al. (1980) found that juveniles grew more quickly when they were raised on brine shrimp nauplii than tubifex worms. Many biologists have concluded these fishes are no more effective in mosquito-larval control than various native fishes (Cross 1967). The effectiveness of predation on mosquito larvae decreases as water volume decreases (Reddy and Pandian 1973).

Length: 6 centimeters
Economic Attributes Not yet assessed
Management Summary
Stewardship Overview: The spread of mosquitofish outside its native range should be monitored and necessary steps taken to: (1) understand the competitive edge it has over native species, (2) limit its introduction or invasion into new locations, and (3) evaluate the possible benefit of eradication efforts in locations that can be rehabilitated for native fishes.
Species Impacts: Outside their native range, mosquitofish play a role in decreasing populations of native fishes (Miller 1961, Myers 1965, Minckley and Deacon 1968). Due to the number of introductions and corresponding decreases in native fish populations, there can be no doubt of the destructive nature of such introductions. Myers (1965) wrote that almost everywhere introductions have been made, mosquitofish have gradually eliminated or reduced populations of small native fishes. For example, mosquitofish have been instrumental in eliminating native populations of Poeciliopsis occidentalis in the southwestern U.S. (Sublette et al. 1990); P. occidentalis may be effectively eliminated in 1-3 years (Meffe 1984). Evermann and Clark (1931) reported that mosquitofish in the Salton Sea, California, drove out Cyprinodon macularius less than 10 years after introduction to the state. The mechanism for many of these reductions is believed to be predation (Meffe 1985, Courtenay and Meffe 1989). Myers (1965) reported that mosquitofish have even reduced largemouth bass (Micropterus salmoides) and carp (Cyprinus carpio) populations due to predation on larvae. Another problem is caused when mosquitofish hybridize with other Gambusia species (Yardley and Hubbs 1976, Rutherford 1980). Intergradation then corrupts the genome of the native species.

Introduced mosquitofish also prey heavily on amphibian larvae (Goodsell and Kats 1999) and potentially negatively impact salamander and frog populations (Lawler et al. 1999).

Restoration Potential: Not applicable.
Preserve Selection & Design Considerations: Lands do not need to be protected to provide adequate habitat within the native range.
Management Requirements: It is unclear whether management activities can control this fish. Eradication efforts have often been temporarily successful, but either not all individuals were killed or reintroductions were made. Certainly, eradication efforts must be followed with intensive monitoring. Preventative measures, such as barrier construction to obstruct the paths into uncolonized tributaries, should be taken when feasible. Transport and introduction of non-native fishes should be curtailed. Natural flooding regimes in western streams could aid in keeping populations in check. Meffe (1984, 1985) showed that flooding removes proportionally more mosquitofish than native topminnows.

Regulations should be drafted and/or enforced that discourage transport and stocking of non-native fishes into uncolonized habitats. An education program targeted at fishers relating the damage non-native fishes do to the environment should be implemented. An education program targeted at state and federal agencies should be implemented explaining the detrimental impact of stocking mosquitofish for mosquito larvae control. Natural barriers can be enhanced, or new barriers built to prevent the invasion of non-native fishes. Barrier design should not significantly alter stream flow and the potential impact on natural upstream and downstream movements of native fishes should be assessed. Barrier design must be approved by appropriate agencies and the appropriate Desert Fishes Recovery Teams.

Monitoring Requirements: Populations should be monitored at the periphery of their native and introduced ranges. This data will provide information on their spread. It is possible that in certain situations, eradication efforts can be made in newly colonized habitats outside of the native range.

When populations are discovered in a new location outside the native range, a monitoring program should be initiated. Due to the rapid rate of increase and colonization potential, monitoring stations should be set-up in the affected stream and adjacent tributaries. Distances between stations will depend on variation in habitat and permanency of flow. Mosquitofish are usually easily seined and dip-netted, although small mesh sizes should be used to sample juveniles. Due to their habit of swimming just under the water surface, they can be spotted before a collecting effort is made.

Management Research Needs: Because this is a wide ranging eastern species, much of the biology is known in the native habitat. The following specific topics are research areas that should be addressed relative to locations where introductions have been made: (1) rate of colonization in stream reaches after flooding events or after new introductions, (2) competition for food with native species, comparing diets of all life stages, (3) reproductive potential in introduced locations, emphasizing comparisons with native species, (4) aggression and predation directed towards native species in field studies, and (5) an evaluation of past eradication efforts, and (6) an analysis of sites where mosquitofish and native species have coexisted for several years (e.g. Black Draw, San Bernardino National Wildlife Refuge), and comparison to sites where mosquitofish and native species do not coexist.
Population/Occurrence Delineation
Group Name: Livebearers (Poeciliids)

Use Class: Not applicable
Minimum Criteria for an Occurrence: Occurrences are based on evidence of historical presence, or current and likely recurring presence, at a given location. Such evidence minimally includes collection or reliable observation and documentation of one or more individuals in appropriate habitat.
Separation Barriers: Dam lacking a suitable fishway; high waterfall; upland habitat.
Alternate Separation Procedure: Each spring system that is undivided by a barrier constitutes a single distinct occurrence. Otherwise, use a separation distance of 10 km for any type of aquatic habitat.
Separation Justification: Separation distance is arbitrary. Because of the difficulty in defining suitable versus unsuitable habitat, especially with respect to dispersal, and to simplify the delineation of occurrences, a single separation distance is used regardless of habitat quality.
Date: 21Sep2004
Author: Hammerson, G.
Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
NatureServe Conservation Status Factors Edition Date: 03Feb2012
NatureServe Conservation Status Factors Author: Hammerson, G.
Management Information Edition Date: 21Feb2003
Management Information Edition Author: Vives, Stephen P.
Element Ecology & Life History Edition Date: 03Feb2012
Element Ecology & Life History Author(s): Vives, S. P., and G. Hammerson

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

  • Ahuja, S. K. 1964. Salinity tolerances of Gambusia affinis. Indian Journal of Experimental Biology 2:9-11.

  • Al-Daham, N. K., and M. N. Bhatti. 1977. Salinity tolerance of Gambusia affinis (Baird and Girard) and Heterpneustes fossilis (Bloch). Journal of Fish Biology 11:309-13.

  • Allen, C. R., S. Demarais, and R. S. Lutz. 1994. Red imported fire ant impact on wildlife: an overview. The Texas Journal of Science 46(1):51-59.

  • Anderson, Allison A., C. Hubbs, K. O. Winemiller, and R. J. Edwards. 1995. Texas freshwater fish assemblages following three decades of environmental change. The Southwest Naturalist 40(3):314-321.

  • Bacon, E. J., Jr., W. H. Neill, Jr., and R. B. Kilambi. 1968. Temperature selection and heat resistance of the mosquitofish, Gambusia affinis. Proceedings of the Annual Conference of the Southeastern Association of Game and Fish Commissioners 22:411-416

  • Bahr, L.M. and J.J. Hebrard. 1976. Barataria Basin: Biological Characterization. CWR, LSU. Sea Grant Publication No. LSU-T-76-005.

  • Baird, S. F., and C. Girard. 1853. Descriptions of new species of fishes collected by Captains R. B. Marcy, and Geo. B. M'Clellan, in Arkansas. Proceedings of the Academy of Natural Sciences of Philadelphia 6:390-2.

  • Barney, R. L., and B. J. Anson. 1921. Seasonal abundance of the mosquito destroying top-minnow, Gambusia affinis, especially in relation to fecundity. Anatomical Record 22:317-335.

  • Barnickol, P. G. 1941. Food habits of Gambusia affinis from Reelfoot Lake, Tennessee, with special reference to malarial control. Report of the Reelfoot Lake Biological Station 5:5-13.

  • Bence, J. R., and W. W. Murdoch. 1986. Prey size selection by the mosquitofish: relation to optimal diet theory. Ecology 67:324-336.

  • Bennett, D. H., and C. P. Goodyear. 1978. Response of mosquitofish to thermal effluent. Pages 498-510 in J. H. Thorp and J. W. Gibbons (editors). Energy and Environmental Stress in Aquatic Systems. Technical Information Center, U.S. Department of Energy Symposium Series. CONF-771114.

  • Black, D. A., and W. M. Howell. 1979. The North American mosquitofish, Gambusia affinis: a unique case in sex chromosome evolution. Copeia 1979:509-513.

  • Brown, C. J. D., and A. C. Fox. 1966. Mosquito fish (Gambusia affinis) in a Montana pond. Copeia 1966:614-6.




  • Casterlin, M. E., and W. W. Raynolds. 1977. Aspects of habitat selection in the mosquitofish, Gambusia affinis. Proceedings and Papers of the Annual Conference of the California Mosquito Vector Control Association 48:45-7.

  • Cech, J. J., Jr., M. J. Massingill, and T. E. Wragg. 1980. The food demands of mosquitofish, Gambusia affinis. Proceedings and Papers of the Annual Conference of the California Mosquito Vector Control Association 48:45-47.

  • Collier, Albert. 1936. The mechanism of internal fertilization in Gambusia. Copeia 1936:45-53.

  • Constantz, G. D. 1989. Reproductive biology of poeciliid fishes. Pages 33-50 in G.K. Meffe and F. F. Snelson, Jr. (editors). Ecology and evolution of livebearing fishes (Poeciliidae). Prentice Hall, Englewood Cliffs, New Jersey.

  • Courtenay, W. R., Jr., and G. K. Meffe. 1989. Small fishes in strange places: a review of introduced poeciliids. Pages 319-331 in G.K. Meffe and F. F. Snelson, Jr. (editors). Ecology and evolution of livebearing fishes (Poeciliidae). Prentice Hall, Englewood Cliffs, New Jersey.

  • Cowley, D. W., and J. E. Sublette. 1987. Distribution of fishes in the Black River drainage, Eddy County, New Mexico. Southwestern Naturalist 32:213-221.

  • Cross, F. B. 1967. Handbook of fishes of Kansas. University of Kansas Museum of Natural History Miscellaneous Publication No. 45. 357 pp.

  • Douglas, Neil H. 1974. Freshwater fishes of Louisiana. Claitor's publ. div. Baton Rouge, Louisiana. 443 pp.


  • Etnier, David A. and Wayne C. Starnes. 1993. The Fishes of Tennessee. University of Tennessee Press, Knoxville. 681 pp.

  • Evermann, B. W., and H. W. Clark. 1931. A distributional list of the species of freshwater fishes known to occur in California. California Department of Fish and Game, Fish Bulletin 35:1-67.

  • Farley, D. G., and L. C. Younce. 1977. Some effects of Gambusia affinis (Baird and Girard ) on selected non-target organisms in Fresno County rice fields. Proceedings and Papers of the Annual Conference of the California Mosquito Vector Control Association 45:87-94.

  • Ferens, M. C., and T. M. Murphy, Jr. 1974. Effects of thermal effluents on populations of mosquitofish. Pages 237-45 in Gibbons, J. W., and R. R. Sharitz (editors). Thermal Ecology. AEC Symposium Series, CONF-730505.

  • Goodsell, J. A., and L. B. Kats. 1999. Effect of introduced mosquitofish on Pacific treefrogs and the role of alternative prey. Conservation Biology 13:921-924.

  • Grubb, J. C. 1972. Differential predation by Gambusia affinis on the eggs of seven species of anuran amphibians. American Midland Naturalist 88:102-108.




  • Harrington, R. W., Jr., and E. S. Harrington. 1982. Effects on fishes and their forage organisms of impounding a Florida salt marsh to prevent breeding by salt marsh mosquitoes. Bulletin of Marine Science 32:523-531.

  • Hollander, R. R. 1986. Microanalysis of scales of poeciliid fishes. Copeia 1986:86-91.

  • Hubbs, C. 1971. Competition and isolation mechanisms in the Gambusia affinis x G. heterochir hybrid swarm. Texas Memorial Museum Bulletin No. 19. 46 p.

  • Hunt, B. P. 1953. Food relationships between Florida spotted gar and other organisms in the Tamiami Canal, Dade County, Florida. Transactions of the American Fisheries Society 82:13-33.

  • Hurlbert, S. H., J. Zedler, and D. Fairbanks. 1972. Ecosystem alteration by mosquitofish (Gambusia affinis) predation. Science 175:639-641.

  • Hurlbert, S. H., and M. S. Mulla. 1981. Impacts of mosquitofish (Gambusia affinis) predation on plankton communities. Hydrobiologica 83:125-151.

  • Krumholz, L. A. 1944. Northward acclimatization of the western mosquitofish, Gambusia affinis affinis. Copeia 1944:82-5.

  • Kurmholz, L. A. 1948. Reproduction in the western mosquitofish, Gambusia affinis affinis (Baird and Girard), and its use in mosquito control. Ecological Monographs 18:1-43.

  • Kushlan, J. A. 1974. Effects of a natural fish kill on the water quality, plankton, and fish population of a pond in the Big Cypress Swamp, Florida. Transactions of the American Fisheries Society 103:235-243.

  • La Rivers, I. 1994. Fishes and fisheries of Nevada. University of Nevada Press, Reno. 782 pp.

  • Lam, T. H. 1983. Environmental influences on gonadal activity in fish. Pages 65-116 in W. S. Hoar, D. J. Randall, and E. M. Donaldson (editors). Fish Physiology, Vol. 9B. Academic Press, New York, New York.

  • Lawler, S. P., D. Dritz, T. Strange, and M. Holyoak. 1999. Effects of introduced mosquitofish and bullfrogs on the threatened California red-legged frog. Conservation Biology 13:613-622.

  • Lewis, W. M., Jr. 1970. Morphological adaptations of cyprinodontoids for inhabiting oxygen deficient waters. Copeia 1970:319-326.

  • Lydeard, C., and M. C. Wooten. 1991. Occurrence of Gambusia affinis in the Savannah and Chattahoochee drainages: previously undescribed geographic contacts between G. affinis and G. holbrooki. Copeia 1991:1111-1116.

  • Lynch, J. D. 1992. Anthropochore dispersal of Gambusia affinis and Gambusia holbrooki and their aboriginal distributions. Page 134 in Abstracts from the 72nd Annual Meeting of the American Society of Ichthyologists and Herpetologists (ASIH), Champaign-Urbana, Illinois.


  • Maglio, V. J., and D. E. Rosen. 1969. Changing preference for substrate color by reproductively active mosquitofish, Gambusia affinis (Baird and Girard) (Poeciliidae, Atheriniformes). American Museum Novitates 2397.

  • Martin, R. G. Sexual and aggressive behavior, density and social structure in a natural population of mosquitofish, Gambusia affinis holbrooki. Copeia 1975:445-54.

  • McGinnis, S. M. 1984. Freshwater fishes of California. University of California Press, Berkeley, California. viii + 316 pp.

  • Meffe, G. K. 1984. Effects of abiotic disturbance on coexistence of predator-prey fish species. Ecology 65:1525-1534.

  • Meffe, G. K. 1985. Predation and species replacement in American southwestern fishes: a case study. Southwestern Naturalist 30:173-187.

  • Meffe, G. K., D. A. Hendrickson, W. L. Minckley and J. N. Rinne. 1983. Factors resulting in decline of the endangered Sonoran topminnow (Atheriniformes: Poeciliidae) in the United States. Biological Conservation 25:135-59.

  • Meffe, G. K., and F. F. Snelson, Jr., editors. 1989. Ecology and evolution of livebearing fishes (Poeciliidae). Prentice Hall, Englewood Cliffs, New Jersey. 453 pp.

  • Meffe, G. K., and M. L. Crump. 1987. Possible growth and reproductive benefits of cannibalism in the mosquitofish. American Naturalist 129(2):203-212.

  • Miller, R. R. 1961. Man and the changing fish fauna of the American Southwest. Papers of the Michigan Academy of Science, Arts and Letters 46:365-404.

  • Miller, R. R., and C. H. Lowe. 1967. Part 2: The fishes of Arizona. Pages 133-151 in Lowe, C. H. (editor). The Vertebrates of Arizona. University of Arizona Press, Tuscon, Arizona.

  • Minckley, W. L. 1973. Fishes of Arizona. Arizona Game and Fish Department, Phoenix, Arizona. 293 pp.

  • Minckley, W. L., G. K. Meffe, and D. L. Soltz. 1991a. Conservation and management of short-lived fishes: the cyprinodontoids. Pages 247-82 in W. L. Minckley and J. E. Deacon (editors). Battle Against Extinction: Native Fish Management in the American West. University of Arizona Press, Tucson, Arizona.

  • Minckley, W. L., and J. E. Deacon. 1968. Southwestern fishes and the enigma of "endangered species." Science 159:1424-32.

  • Moyle, P. B. 1976a. Inland fishes of California. University of California Press, Berkeley, California. 405 pp.

  • Moyle, P. B. 2002. Inland fishes of California. Revised and expanded. University of California Press, Berkeley. xv + 502 pp.

  • Mushinsky, H. R., and J. J. Hebrard. 1977. Food partitioning by five species of water snakes in Louisiana. Herptetologica 33:162-166.

  • Myers, G. S. 1965. The fish destroyer. Tropical Fish Hobbyist 1965:31-5.

  • Nelson, J. S., E. J. Crossman, H. Espinosa-Perez, L. T. Findley, C. R. Gilbert, R. N. Lea, and J. D. Williams. 2004. Common and scientific names of fishes from the United States, Canada, and Mexico. American Fisheries Society, Special Publication 29, Bethesda, Maryland. 386 pp.

  • Odum, W. E. 1971. Pathways of energy flow in a south Florida estuary. University of Miami Sea Grant Technical Bulletin No. 7, Miami, Florida.

  • Otto, R. G. 1973. Temperature tolerance of the mosquitofish, Gambusia affinis (Baird and Girard). Journal of Fish Biology 5:575-85.


  • Page, L. M., H. Espinosa-Pérez, L. T. Findley, C. R. Gilbert, R. N. Lea, N. E. Mandrak, R. L. Mayden, and J. S. Nelson. 2013. Common and scientific names of fishes from the United States, Canada, and Mexico. Seventh edition. American Fisheries Society, Special Publication 34, Bethesda, Maryland.

  • Page, L. M., and B. M. Burr. 1991. A field guide to freshwater fishes: North America north of Mexico. Houghton Mifflin Company, Boston, Massachusetts. 432 pp.

  • Page, L. M., and B. M. Burr. 2011. Peterson field guide to freshwater fishes of North America north of Mexico. Second edition. Houghton Mifflin Harcourt, Boston. xix + 663 pp.

  • Page, LM, H.Espinoza-Perez, L.Findley, C.Gilbert, R. Lea, N. Mandrak, R.Mayden and J.Nelson. 2013. Common and scientific names of fishes from the United States, Canada, and Mexico, 7th edition. American Fisheries Society, Special Publication 34, Bethesda, Maryland.

  • Peden, A. E. 1973. Variation in anal spot expression of gambussin females and its effect on male courtship. Copeia 1973:250-263.

  • Peden, A. E. 1975. Differences in copulatory behavior as partial isolating mechanisms in the poeciliid fish Gambusia. Canadian Journal of Zoology 53:1290-6.

  • Perry, W. Guthrie, and Brandon J. Carter. Seasonal occurrence of fishes collected from beach seining, Southwest LA. 1979. La. Acad. of Sci. 42( ): 24-38.

  • Propst, D. L., G. L. Burton, and B. H. Pridgeon. 1987. Fishes of the Rio Grande between Elephant Butte and Caballo Reservoirs, New Mexico. The Southwestern Naturalist 32(3): 408-411



  • Rauchenberger, M. 1989. Systematics and biogeography of the genus Gambusia (Cyprinodontiformes: Poecilidae). American Museum Novitates (2951):1-74.

  • Reddy, S. R., and K. Shankuntala. 1979. Comparative studies of the food intake, growth and food conversion of two lavivorous fishes. Proceedings of the Indian National Science Academy 88:425-432.

  • Reddy, S. R., and T. J. Pandian. 1973. Effect of volume of water on predatory efficiency of the fish Gambusia affinis. Current Science 42:644-645.

  • Rees, D. M. 1934. Notes on mosquito fish in Utah. Gambusia affinis (Baird and Girard). Copeia 1934:157-9.

  • Regan, J. D. 1961. Melanism in the poeciliid fish, Gambusia affinis (Baird and Girard). American Midland Naturalist 65:139-43.

  • Robins, C.R., R.M. Bailey, C.E. Bond, J.R. Brooker, E.A. Lachner, R.N. Lea, and W.B. Scott. 1991. Common and scientific names of fishes from the United States and Canada. American Fisheries Society, Special Publication 20. 183 pp.

  • Robins, C.R., R.M. Bailey, C.E. Bond, J.R. Brooker, E.A. Lackner, R.N. Lea, and W.K. Scott. 1980. A List of Common and Scientific Names of Fishes from the US and Canada. 4th edition. American Fisheries Society, Special Publication No. 12, Bethesda, Maryland. 174 pp.

  • Rutherford, D. A. 1980. Hybridization in Gambusia nobilis (Pisces, Poeciliidae): an endangered species in the pecos River drainage of Texas and New Mexico. Baylor University, Waco, Texas. M.S. Thesis.


  • Salibian, A. 1977. Aclimatacion de Gambusia affinis holbrooki (Girard 1859) de Chile en soluciones de alta salinidad. Noticiario Mensual del Museo Nacional de Historia Natural (Chile) 22:4-7.

  • Scribner, K. T. 1993. Hybrid zone dynamics are influenced by genotype-specific variation in life-history traits: experimental evidence from hybridizing Gambusia species. Evolution 47:632-646.

  • Seale, A. 1917. The mosquito fish, Gambusia affinis (Baird and Girard) in the Phillippine Islands. Phillippine J. Sci. 12:177-87.

  • Shakuntala, K., and R. Reddy. 1979. Influence of temperature-salinity combinations on the food intake, growth and converstion efficiency of Gambusia affinis (Pisces). Polish Archives of Hydrobiology 26:173-81.

  • Simon, Thomas P. 2011. Fishes of Indiana. Indiana University Press. Bloomington, 345 pp.

  • Stearns, S. C. 1983a. A natural experiment in life-history evolution: field data on the introduction of mosquito fish (Gambusia affinis) to Hawaii. Evolution 37:601-617.

  • Stearns, S. C. 1983c. The evolution of life-history traits in mosquito fish since their introduction to Hawaii in 1905: rates of evolution, heritabilities, and developmental plasticity. American Zoologist 23:65-75.

  • Stearns, S. C., and R. D. Sage. 1980. Maladaptation in a marginal population of the mosquitofish Gambusia affinis. Evolution 34:65-75.

  • Stearns. S. C. 1984. Heritability estimates for age and length at maturity in two populations of mosquito fish that shared ancestors in 1905. Evolution 38:368-375.

  • Suhr, J. M., and J. D. Davis. 1974. The spider Dolomedes sexpunctatus as a predator on mosquitofish, Gambusia affinis, in Mississippi. Association of Southeastern Biologists Bulletin 21:87.

  • Turner, C. L. 1941. Morphogenesis of the gonopodium in Gambusia affinis affinis. Journal of Morphology 69:161-85.

  • Turner, J. S., and F. F. Snelson, Jr. 1984. Population structure, reproduction and laboratory behavior of the introduced Belonesox belizanus (Poeciliidae) in Florida. Environmental Biology of Fishes 10:89-100.




  • Walters, D. M., and B. J. Freeman. 2000. Distribution of Gambusia (Poeciliidae) in a southeastern river system and use of fin ray counts for species determination. Copeia 2000:555-559.

  • Walters, L. L., and E. F. Legner. 1980. Impact of the desert pupfish, Cyprinodon macularius, and Gambusia affinis affinis on fauna in pond ecosystems. Hilgardia 48:1-18.

  • Winkler, P. 1979. Thermal preference of Gambusia affinis affinis as determined under field and laboratory conditions. Copeia 1979:60-64.

  • Woodling, J. 1985. Colorado's Little Fish: A Guide to the Minnows and Other Lesser Known Fishes in the State of Colorado. Colorado Division of Wildlife, Denver.

  • Woodling, J. 1985. Colorado's little fish: a guide to the minnows and other lesser known fishes in the state of Colorado. Colorado Division of Wildlife, Denver. 77 pp.

  • Wooten, M. C., K. T. Scribner, and M. H. Smith. 1988. Genetic variability and systematics of Gambusia in the southeastern United States. Copeia 1988:283-289.

  • Wurtsbaugh, W. A., J. J. Check, Jr. and J. Compton. 1980. Effect of fish size on prey size selection in Gambusia affinis. Proceedings and Papers of the Annual Conference of the California Mosquito Vector Control Association 48:48-51.

  • Yardley, D. and C. Hubbs. 1976. An electrophoretic study of two species of mosquitofish with notes on genetic subdivision. Copeia 1976:117-20.

  • Zimmerer, E. G. 1983. Effect of salinity on the size-hierarchy effect in Poecilia latipinna, P. reticulata and Gambusia affinis. Copeia 1983:243-245.

References for Watershed Distribution Map
  • Boschung, H. T., and R. L. Mayden. 2004. Fishes of Alabama. Smithsonian Institution Press, Washington, D.C. 960 pp.

  • Burr, B. M., and M. L. Warren, Jr. 1986a. Distributional atlas of Kentucky fishes. Kentucky Nature Preserves Commission, Scientific and Technical Series No. 4, Frankfort, Kentucky. 398 pp.

  • Douglas, N. H. 1974. Freshwater fishes of Louisiana. Claitor's Publishing Division, Baton Rouge, Louisiana. 443 pp.

  • Etnier, D. A., and W. C. Starnes. 1993. The fishes of Tennessee. University of Tennessee Press, Knoxville, Tennessee. xiv + 681 pp.

  • Lee, D. S., C. R. Gilbert, C. H. Hocutt, R. E. Jenkins, D. E. McAllister, and J. R. Stauffer, Jr. 1980. Atlas of North American freshwater fishes. North Carolina State Museum of Natural History, Raleigh, North Carolina. i-x + 854 pp.

  • Mettee, M. F., P. E. O'Neil, and J. M. Pierson. 1996. Fishes of Alabama and the Mobile Basin. Oxmoor House, Birmingham, Alabama. 820 pp.

  • Pflieger, W. L. 1975. The fishes of Missouri. Missouri Department of Conservation. Columbia, Missouri. viii + 343 pp.

  • Robison, H. W. and T. M. Buchanan. 1988. Fishes of Arkansas. The University of Arkansas Press, Fayetteville, Arkansas. 536 pp.

  • Ross, S. T., and W. M. Brenneman. 1991. Distribution of freshwater fishes in Mississippi. Freshwater Fisheries Report No. 108. D-J Project Completion Report F-69. Mississippi Department of Wildlife and Freshwater Fisheries and Parks. Jackson, Mississippi. 548 pp.

  • Smith, P. W. 1979. The fishes of Illinois. University of Illinois Press, Urbana. 314 pp.

  • Sublette, J. E., M. D Hatch, and M. Sublette. 1990. The fishes of New Mexico. University New Mexico Press, Albuquerque, New Mexico. 393 pp.

Use Guidelines & Citation

Use Guidelines and Citation

The Small Print: Trademark, Copyright, Citation Guidelines, Restrictions on Use, and Information Disclaimer.

Note: All species and ecological community data presented in NatureServe Explorer at were updated to be current with NatureServe's central databases as of March 2018.
Note: This report was printed on

Trademark Notice: "NatureServe", NatureServe Explorer, The NatureServe logo, and all other names of NatureServe programs referenced herein are trademarks of NatureServe. Any other product or company names mentioned herein are the trademarks of their respective owners.

Copyright Notice: Copyright © 2018 NatureServe, 4600 N. Fairfax Dr., 7th Floor, Arlington Virginia 22203, U.S.A. All Rights Reserved. Each document delivered from this server or web site may contain other proprietary notices and copyright information relating to that document. The following citation should be used in any published materials which reference the web site.

Citation for data on website including State Distribution, Watershed, and Reptile Range maps:
NatureServe. 2018. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available (Accessed:

Citation for Bird Range Maps of North America:
Ridgely, R.S., T.F. Allnutt, T. Brooks, D.K. McNicol, D.W. Mehlman, B.E. Young, and J.R. Zook. 2003. Digital Distribution Maps of the Birds of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Bird Range Maps of North America:
"Data provided by NatureServe in collaboration with Robert Ridgely, James Zook, The Nature Conservancy - Migratory Bird Program, Conservation International - CABS, World Wildlife Fund - US, and Environment Canada - WILDSPACE."

Citation for Mammal Range Maps of North America:
Patterson, B.D., G. Ceballos, W. Sechrest, M.F. Tognelli, T. Brooks, L. Luna, P. Ortega, I. Salazar, and B.E. Young. 2003. Digital Distribution Maps of the Mammals of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Mammal Range Maps of North America:
"Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy-Migratory Bird Program, Conservation International-CABS, World Wildlife Fund-US, and Environment Canada-WILDSPACE."

Citation for Amphibian Range Maps of the Western Hemisphere:
IUCN, Conservation International, and NatureServe. 2004. Global Amphibian Assessment. IUCN, Conservation International, and NatureServe, Washington, DC and Arlington, Virginia, USA.

Acknowledgement Statement for Amphibian Range Maps of the Western Hemisphere:
"Data developed as part of the Global Amphibian Assessment and provided by IUCN-World Conservation Union, Conservation International and NatureServe."

NOTE: Full metadata for the Bird Range Maps of North America is available at:

Full metadata for the Mammal Range Maps of North America is available at:

Restrictions on Use: Permission to use, copy and distribute documents delivered from this server is hereby granted under the following conditions:
  1. The above copyright notice must appear in all copies;
  2. Any use of the documents available from this server must be for informational purposes only and in no instance for commercial purposes;
  3. Some data may be downloaded to files and altered in format for analytical purposes, however the data should still be referenced using the citation above;
  4. No graphics available from this server can be used, copied or distributed separate from the accompanying text. Any rights not expressly granted herein are reserved by NatureServe. Nothing contained herein shall be construed as conferring by implication, estoppel, or otherwise any license or right under any trademark of NatureServe. No trademark owned by NatureServe may be used in advertising or promotion pertaining to the distribution of documents delivered from this server without specific advance permission from NatureServe. Except as expressly provided above, nothing contained herein shall be construed as conferring any license or right under any NatureServe copyright.
Information Warranty Disclaimer: All documents and related graphics provided by this server and any other documents which are referenced by or linked to this server are provided "as is" without warranty as to the currentness, completeness, or accuracy of any specific data. NatureServe hereby disclaims all warranties and conditions with regard to any documents provided by this server or any other documents which are referenced by or linked to this server, including but not limited to all implied warranties and conditions of merchantibility, fitness for a particular purpose, and non-infringement. NatureServe makes no representations about the suitability of the information delivered from this server or any other documents that are referenced to or linked to this server. In no event shall NatureServe be liable for any special, indirect, incidental, consequential damages, or for damages of any kind arising out of or in connection with the use or performance of information contained in any documents provided by this server or in any other documents which are referenced by or linked to this server, under any theory of liability used. NatureServe may update or make changes to the documents provided by this server at any time without notice; however, NatureServe makes no commitment to update the information contained herein. Since the data in the central databases are continually being updated, it is advisable to refresh data retrieved at least once a year after its receipt. The data provided is for planning, assessment, and informational purposes. Site specific projects or activities should be reviewed for potential environmental impacts with appropriate regulatory agencies. If ground-disturbing activities are proposed on a site, the appropriate state natural heritage program(s) or conservation data center can be contacted for a site-specific review of the project area (see Visit Local Programs).

Feedback Request: NatureServe encourages users to let us know of any errors or significant omissions that you find in the data through (see Contact Us). Your comments will be very valuable in improving the overall quality of our databases for the benefit of all users.