Invasion History

First Non-native North American Tidal Record: 1958
First Non-native West Coast Tidal Record: 1958
First Non-native East/Gulf Coast Tidal Record:

General Invasion History:

Rainwater Killifish (Lucania parva) is native to Atlantic Coast from Cape Cod, Massachusetts, to the Florida Keys and Quintana Roo, Mexico. Its most commonly found in estuaries, not far above the tideline, however, it ranges far into non-tidal freshwaters is several rivers that have mineral-rich waters, including the St. Johns River, Florida, and the Rio Grande-Pecos system of Texas-New Mexico (Hubbs and Miller 1965; Robins et al. 1986; Page and Burr 1991; US National Museum of Natural History 2009). It has been introduced in the Western United States where it was discovered in four separate locations from 1958 to 1961 (Hubbs and Miller 1965).

North American Invasion History:

Invasion History on the West Coast:

In 1958 to 1963, populations of the Rainwater Killifish (L. parva) were discovered almost simultaneously in five separate areas of the Western United States. Populations were discovered in the San Francisco Estuary, Yaquina Bay, Oregon, Irvine Lake (Orange County, California), Blue Lake and Timpie Springs (both in Utah). Hubbs and Miller (1965) noted that Irvine Lake and the Utah sites all received Largemouth Bass (Micropterus salmoides) raised in a hatchery in Dexter, New Mexico, on the Pecos River, a Rio Grande tributary which has native Rainwater Killifish populations, and considered this the vector for the introductions. However, they did not find documentation for gamefish transfers from the Dexter Hatchery to the San Francisco Bay or Yaquina watersheds, and based on meristic and morphometric similarities to Atlantic Coast fish, that Rainwater Killifish had been introduced from the East Coast with Eastern Oysters (Hubbs and Miller 1965). However, plantings of Redear Sunfish (Lepomis microlophus) from the Dexter hatchery were made in the San Joaquin valley in the 1950s (Shapalov et al. 1959, cited by Cohen and Carlton 1995). Since the Dexter hatchery was a major source for warm water gamefish in the West, and the discoveries were so simultaneous, a single source seems likely. The merisitic similarities of the West Coast populations to Atlantic populations are small and could be explained by adaptation to an estuarine habitat (Cohen and Carlton 1995).

In May 1958, Rainwater Killifish were discovered in Berkeley Aquatic Park on San Francisco Bay. It was subsequently discovered in several locations, mostly sloughs and lagoons on the Central Bay (Richmond), Oakland (Merrit Slough), Corte Madera Creek), the South Bay (Palo Alto), and San Pablo Bay (Sonoma Creek) (Hubbs and Miller 1965). By the 1970s, it was abundant in Suisun Marsh (Matern et al. 2002). It has been found in the lower reaches of 25 San Francisco Bay tributaries (Leidy 2007), and in salt ponds adjacent to South San Francisco Bay at salinities up to 50 PSU (Mejia et al. 2008). In 1963, this fish was found in Lake Irvine, a reservoir in the interior of Orange County (Hubbs and Miller 1965). Again, this population is believed to be established, though we are unaware of recent records (Swift et al. 1993). An established population was found at Goleta Point, on the University of California Campus in Santa Barbara in the early 1980s (Swift et al. 1993). In July 1958, another population of L. parva was found in several sloughs near Yaquina Bay, Oregon (1958, Hubbs and Miller 1965). We assume that this fish is still established there, but we have found no recent records.

Invasion History Elsewhere in the World:

In 1959 Rainwater Killifish (L. parva) were found in Timpie Spring, on the shore of Great Salt Lake, Utah. Since then, this fish has been found elsewhere in the Great Salt Lake Basin basin, in Blue Lake (Hubbs and Miller 1965) and in Utah Lake (Lee et al. 1980).


The Rainwater Killifish (Lucania parva) is a small, mostly estuarine fish, but it has some breeding freshwater populations and does enter marine waters (Hildebrand and Schroeder 1928; Page and Burr 1991; Fuller and Noa 2008). Killifish of the family Fundulidae have a somewhat streamlined body, with soft-rayed dorsal and anal fins, a rounded or squareish tail, abdominal pelvic fins, and moderate-sized scales, and a small, upturned mouth. The origin of the dorsal fin is anterior to that of the anal fin. This fish has 20 to 23 lateral line scales, and 9-13 dorsal rays. The body is laterally compressed, and deep, compared to the Bluefin Killifish (L. goodei.) The Rainwater Killifish is small, up to 70 mm long, but more usually ~32 mm. The back of the fish is dusky to olive brown, and the sides are silvery-white, white, with a faint dusky-orange stripe from the edge of the gill-cover to the base of the tail. The scales are large, with dark borders. Males tend to be smaller than females, and have a black spot at the anterior edge of the dorsal fin. During the breeding season, males have orange edges to the pelvic and anal fins (Hardy 1978; Robins et al. 1986; Page and Burr 1991; Murdy et al. 1997; Moyle 2002; Froese and Pauly 2018).


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Chordata
Subphylum:   Vertebrata
Superclass:   Osteichthyes
Class:   Actinopterygii
Subclass:   Neopterygii
Infraclass:   Teleostei
Superorder:   Acanthopterygii
Order:   Cyprinodontiformes
Suborder:   Cyprinodontoidei
Family:   Fundulidae
Genus:   Lucania
Species:   parva


Cyprinodon parvus (Baird & Girard, 1855)
Limia venusta (Girard, 1858)
Lucania affinis (Girard, 1859)

Potentially Misidentified Species

Fundulus diaphanus
Fundulus diaphanus (California Killifish) is native to Eastern North America from Newfoundland to South Carolina, west to Manitoba and Illinois, in fresh and brackish waters. It has been introduced in the Columbia River. The California Killifish is olive dorsally and yellowish-brown below, with green-brown bars along the sides. Adults can reach 130 mm, but juveniles could be confused with Lucania parva (Page and Burr 1991).

Fundulus parvipinnis
Fundulus parvipinnis (California Killifish) is native to the Pacific Coast from Morro Bay to Baja California in shallow bays and salt marshes. This fish is olive dorsally and yellowish-brown below, with dark bars along the sides. Adults can reach 110 mm, but juveniles could be confused with Lucania parva (Eschmeyer and Herald 1983).

Lucania goodei
Lucania goodei (Bluefin Killifish) is more slender, with a zigzag black stripe from nose to tail. Males have bright blue fins (Page and Burr 1991). This killifish has been found in the San Dieguito River and the Sacramento-San Joaquin Delta but is not known to be established.



Over most of its range, Rainwater Killifish (Lucania parva) is an estuarine species, ranging from euhaline to tidal fresh waters, but nontidal freshwater populations occur far up the Rio Grande and Pecos Rivers in Texas, New Mexico, and Mexico, and on the Florida peninsula, where the 'fresh' waters are slightly saline or highly mineralized (Page and Burr 1991). Males tend to be somewhat more colorful than females and smaller (Hardy 1979; Robins et al. 1986; Page and Burr 1991; Murdy et al. 1997; Froese and Pauly 2018). Fish mature at about 25 mm. Females can carry 7-104 eggs. The spawning time in Chesapeake Bay is April-July, but in Florida they spawn year-round (Hildebrand and Schroeder 1938; Hardy 1978). Males guard territories, but do not make nests. The eggs are demersal and adhesive and are scattered on vegetation. The larvae are initially demersal, but then swim in small schools, often moving into very shallow-water. They can mature in 3-5 months after hatching (Wang 1986).

At the northern end of its range, in southern New England, Rainwater Killifish inhabit estuaries which freeze over in winter, but in Florida and Mexico they range into subtropical waters (Robins et al. 1986; Page and Burr 1991). They are remarkably euryhaline, occurring and breeding at 0-49 PSU (Hardy 1978). Inland freshwater populations occur mostly in alkaline waters with high mineral content, such as the St. Johns River, Florida, and the Rio Grande Basin in Texas, Mexico, and New Mexico (Page and Burr 1991). These fish are sensitive to acidic conditions (Dunson and Travis 1991). The Rainwater Killifish are strongly associated with dense vegetation including Tapegrass (Vallisneria americana), Pondweed (Potamogeton spp.), and Eelgrass (Zostera marina). Rainwater Killifish feeds mostly on small invertebrates (Hildebrand and Schroeder 1928). In experiments they strongly preferred vegetated areas, and preferred them even more in the presence of predators (Largemouth Bass) (Jordan 2002).


annelids, mollusks, amphipods

Trophic Status:




General HabitatFresh (nontidal) MarshNone
General HabitatGrass BedNone
General HabitatSwampNone
General HabitatNontidal FreshwaterNone
General HabitatTidal Fresh MarshNone
General HabitatUnstructured BottomNone
General HabitatOyster ReefNone
General HabitatCanalsNone
General HabitatMangrovesNone
Salinity RangeLimnetic0-0.5 PSU
Salinity RangeOligohaline0.5-5 PSU
Salinity RangeMesohaline5-18 PSU
Salinity RangePolyhaline18-30 PSU
Salinity RangeEuhaline30-40 PSU
Salinity RangeHyperhaline40+ PSU
Vertical HabitatNektonicNone

Tolerances and Life History Parameters

Minimum Temperature (ºC)1Based on geographic range, occurrence in estuaries with ice cover.
Maximum Temperature (ºC)28Keup and Bayless 1964, Neuse River NC.
Minimum Salinity (‰)0Page and Burr (1991, permanent nontidal freshwater populations in more saline 'fresh' waters, eg. St. Johns River, Florida, Rio Grande, Texas-New Mexico)
Maximum Salinity (‰)48Field (Hardy 1978), found in South San Francisco Bay Salt ponds with mean salinities of ~ 50 PSU (Mejia et al. 2008)
Minimum Dissolved Oxygen (mg/l)2Nordlie 2006, Field
Minimum Reproductive Salinity0Rainwater Killifish can reproduce in tidal fresh water, and in regions with alkaline, mineralized freshwaters (Page and Burr 1991).
Maximum Reproductive Salinity30Highest tested (Fuller 2008)
Minimum Length (mm)25Size at maturity (Hardy 1978)
Maximum Length (mm)70Page and Burr 1991, but more usually to 37 mm (Froese and Pauly 2018).
Broad Temperature RangeNoneCold Temperate-Subtropical
Broad Salinity RangeNoneNontidal Limnetic-Hyperhaline

General Impacts

Extirpation of the endangered Tidewater Gobies (Eucyclogobius newberryi) in the San Francisco estuary followed the invasion of Rainwater Killifish (Lucania parva) (Hubbs & Miller 1965; Leidy 1984). In experiments, the presence of Rainwater Killifish in aquaria did not affect the growth rate or cortisol levels of Tidewater Gobies (Chase and Todgham 2016). Adverse effects of Rainwater Killifish do not appear to result from food competition or stress, but may be due to displacement by faster reproduction and greater environmental tolerance (Chase et al. 2016).

Regional Impacts

NEP-VNorthern California to Mid Channel IslandsEcological ImpactPredation
Several extirpations of tidewater gobies in the San Francisco Bay area followed the invasion of rainwater killifish (Lucania parva) Hubbs & Miller 1965; Leidy 1984) and yellowfin goby (Acanthogobius flavimanus); Brittan et al. 1970).' (Lafferty et al. 1999)
NEP-VNorthern California to Mid Channel IslandsEcological ImpactCompetition
cboIMP_Impact txtIMP_Type IMP_Comments Predation Ecological Impact Several extirpations of tidewater gobies in the San Francisco Bay area followed the invasion of rainwater killifish (Lucania parva) Hubbs & Miller 1965; Leidy 1984) and yellowfin goby (Acanthogobius flavimanus); Brittan et al. 1970).' (Lafferty et al. 1999)
P090San Francisco BayEcological ImpactCompetition
Adverse effects of Rainwater Killifish on the Tidewater Goby do not appear to result from food competition or stress, but may be due to displacement by faster reproduction and greater environmental tolerance (Chase et al. 2016).
P090San Francisco BayEcological ImpactPredation
Several extirpations of tidewater gobies in the San Francisco Bay area followed the invasion of rainwater killifish (Lucania parva) Hubbs & Miller 1965; Leidy 1984) and yellowfin goby (Acanthogobius flavimanus); Brittan et al. 1970).' (Lafferty et al. 1999).

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
NA-ET3 Cape Cod to Cape Hatteras 0 Native Estab
CAR-VII Cape Hatteras to Mid-East Florida 0 Native Estab
CAR-I Northern Yucatan, Gulf of Mexico, Florida Straits, to Middle Eastern Florida 0 Native Estab
NEP-V Northern California to Mid Channel Islands 1958 Def Estab
NEP-IV Puget Sound to Northern California 1958 Def Estab
P090 San Francisco Bay 1958 Def Estab
S180 St. Johns River 0 Native Estab
G330 Lower Laguna Madre 0 Native Estab
CAR-II None 0 Native Estab
NEP-VI Pt. Conception to Southern Baja California 1985 Def Unk
P065 _CDA_P065 (Santa Barbara Channel) 1985 Def Unk
P210 Yaquina Bay 1958 Def Estab
GRSALTLK Great Salt Lake 1959 Def Estab
M010 Buzzards Bay 0 Native Estab
M013 _CDA_M013 (Cape Cod) 0 Native Estab
M130 Chesapeake Bay 0 Native Estab
M020 Narragansett Bay 0 Native Estab
M040 Long Island Sound 0 Native Estab
M060 Hudson River/Raritan Bay 0 Native Estab
M090 Delaware Bay 0 Native Estab
S020 Pamlico Sound 0 Native Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


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