Gambusia Control Homepage

Welcome to the gambusia control homepage, dedicated to ongoing investigation of the effect of gambusia on native aquatic fauna, and exploration of potential means of control. This page will be of interest to scientists, aquarists, and environmentalists. While many of the examples here come from specific geographic regions like Australia, New Zealand, and North America most of the issues are common across the worldwide distribution of gambusia.

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Gambusia holbrooki, the "fish destroyer." The upper fish is the female, note the gonopodium (a modified anal fin) on the male. Scalebar represents 1 cm.

Gambusias have traditionally been referred to as mosquitofish based on the assumption they are ideal for mosquito larvae control. While we prefer to retain gambusia in the title to this page (since this allows for world wide understanding), we would like to suggest adoption of a more suitable name for these species outside their natural range, damnbusia. This is not an effort to damn this poor innocent fish, but to inform the masses that this species can be a major pest and in many cases more suitable alternatives exist for mosquito larvae control. Hence we feel the name is far more educational and valuable than the misnomer of mosquitofish.

Many people ask what should we use for mosquito control if we can't use mosquitofish? Pretty much any fish will eat mosquito larvae. Try finding a mosquito larvae in any body of water inhabited by fish. The best thing to use is a native fish found in your local area that is somewhat hardy and will reproduce in the environment that requires mosquito control. Which species this is will totally depend upon where in the world you live, but most parts of the world have suitable species that probably already exist in your vicinity. And please stick to using fish from your local river basin, rather than the same or similar species brought in from outside your local river basin as significant differences often exist between populations from different river basins.

Please , any additional pertinent information we could add to the page, and/or indicate if you would like to be included in the gambusia control network (at the end of the text). Ultimately we would like this to become a valuable reference site for people to use in any way they can in their efforts to improve the realms of their favourite native aquatic critters.

This concept, and the bulk of the content of this page were the original brainchild of The page and the server it is on are maintained by We both add additional content as needs and time allows. Last major update was on 2nd November 1998, but additional references and links get added regularly.

Interspecific competition for resources may extend to predation, by gambusia, of eggs and larvae of endemic fishes and amphibians. Milton & Arthington (1982) and Courtenay & Meffe (1989) listed reports that implicated gambusia in the decline of various native fishes. In Australia, gambusia was suggested to be an imminent threat to red finned blue eye (Scaturiginichthys vermeilipinnis, Pseudomugilidae) and Edgbaston goby (Chlamydogobius squamigenus, Gobiidae) (Unmack & Brumley, 1991; Unmack, 1992; Wager, 1994, 1995; Wager & Unmack, in prep). They also negatively effect southern blue eye (Pseudomugil signifer) populations (Howe et al., 1997) and tadpoles (Morgan & Buttemer, 1997; Webb & Joss, 1997). Glover (1989) reported gambusia caused a decrease in desert goby (Chlamydogobius eremius) and spangled perch (Leiopotherapon unicolor, Terapontidae) populations inhabiting Clayton Bore in South Australia. Speculation that gambusia preyed on the eggs and larvae of rainbowfish (Melanotaeniidae) in the wild (Arthington & Lloyd, 1989; Arthington, 1991) was confirmed over summer 1997/98 in a field study in the upper Orara River, near Karangi, New South Wales (Ivantsoff & Aarn, 1999). In New Zealand, Barrier & Hicks (1994) showed that although gambusia was harassed by the larger black mudfish (Neochanna diversus, Galaxiidae), gambusia ate their larvae.

Many examples from North America demonstrate the negative effects of gambusia. Due in large part to predation, gambusia have eliminated Gila topminnow (Poecilliopsis o. occidentalis) from almost it's entire range. Populations only persist where gambusia are absent or in a few springs where other as yet unknown ecological characters allow them to coexist (Minckley et al. 1991). The other subspecies, the Yaqui topminnow (P. o. sonoriensis) is also in great danger as gambusia are only just starting to invade and spread throughout the Yaqui River system. Gambusia have a major impact on some pupfish (Cyprinodon spp.) populations. While no extinctions due to this have been recorded, coexisting populutions tend to be quite depressed in abundance. Evidence collected in part by Unmack (unpub. data) from Ash Meadows, Nevada suggests that when gambusia are decreased in abundance by physical removal, significantly higher numbers of pupfish occur within a year. Gambusia have also been demonstrated to cause extinction of California newt (Taricha torosa populations (Gamradt & Kats, 1996). Much to Diamond's amazement gambusia are freely given out to anyone who wants them in southern California. To directly quote Diamond (1996);

"I phoned the Los Angeles County [West Vector Control] ... District at 310-915-7370. In answer to my questions, a staff member told me: "Yes, they would give me mosquitofish; no, there would be no cost to me; no, I would not have to identify myself, fill out an application or explain what I intended to do with the fish; no, the fish are harmless and present no dangers of which I should be aware; yes, I could have 100 of them"."

In summary, there is ample evidence that gambusia poses a threat to endemic species in parts of Australia, New Zealand, and North America. Hence the need to develop a gambusia control strategy. Complete eradication is unlikely to be attainable, and may not be desirable. Some options concerning biological agents are considered below. Other options, including alteration of water flow rate, netting, and application of piscicides have been trialed but are presently outside the scope of this discussion.

Proposed biological control strategies for vertebrate pests require thorough preliminary evaluation of the risks posed to endemic and/or domesticated species. Cyprinodontiformes is thought to have originated in the Cretaceous Period (Parenti, 1981) and is native to the New and Old Worlds, west of Wallace's line. Therefore, in designing a strategy for biological control of gambusia in Australia and New Zealand, disease agents specific to Cyprinodontiformes could be considered.

Biological control agents vary in pathogenicity towards, and/or specificity for, target hosts. Pathogenicity can be altered (enhanced or attenuated) by selective passage in host or model systems, while specificity is usually not amenable to manipulation.

Perlmutter & Potter (1987) reported a retrovirus, associated with melanoma formation, in a poeciliid. However, there is evidence suggesting that some viruses have jumped species barriers (including the canine parvovirus pandemic in 1977/78, which may have evolved from the feline enteritis virus in laboratory-maintained cats; the possible transfer of HIV-AIDS from primates to humans in the 1960s; and the avian influenza concern of 1997/98). Considerable expertise, and investment, is usually required to ensure quarantine facilities function effectively. Viral control of gambusia is not presently practical.

Many bacterial and fungal disease agents are limited spectrum opportunist pathogens, such as Bacillus thuringiensis (toxic to insects) and the fungus Aspergillus spp. (pathogenic to birds). However, Saprolegnia spp. fungi commonly isolated from wounded fish, and Vibrio spp. frequently cultured from dead fish, appear to be non-host specific, and of enhanced pathogenicity to immune-compromised animals.

Gambusia was reported to host at least 23 parasite species (L. N. Lloyd, cited in Arthington & Lloyd, 1989). Many metazoan parasites (including nematodes and some cestodes) are monoxenous (specific for one host species), but apparently this is not the case in fish. Diseases of fish are relatively poorly characterised, in comparison with diseases of humans and domesticated animals, and the causative agent(s) less-frequently identified. Hence, the apparent polyxenicity of many fish pathogens (including parasites).

Some protozoan parasites of vertebrates are polyxenous, such as Giardia of mammals, Toxoplasma gondii of felids, Ichthyophthirius multifiliis (Ciliophora) of fish, and many coccidia (Apicomplexa) of fish (Dykova & Lom, 1981; Lom & Dykova, 1995). Others coccidia are virtually monoxenous, such as some eimerian coccidia of domestic poultry, and fish. There does not appear to be any criteria to predict specificity.

Recent reports of protozoa (tabulated below) of gambusia and/or other Cyprinodontiformes are not numerous. Factors limiting natural gambusia populations (Courtenay & Meffe, 1989) may include undescribed endemic parasites.

Gambusia has a competitive advantage over endemic species in some habitats undergoing degradation (particularly decreased flow rate, eutrophication, and floral succession). Disregarding the better-understood factors limiting dispersal of gambusia, including predation, fast flow rate, cold water, and salinity (Schoenherr, 1981; Arthington & Lloyd, 1989; Courtenay & Meffe, 1989; Congdon, 1994; Nordlie & Mirandi, 1996), analysis of reports of unsuccessful introductions (e.g. Haq et al., 1992) suggests that colonisation by gambusia is opportunistic.

While attention has focused on (the expansion of) successful gambusia introductions, the factors responsible for unsuccessful introductions have been largely unreported, or inadequately investigated. Gambusia communities at the margin of established or recently translocated populations may be subject to environmental stress, and prone to parasitism. As gambusia is an omnivorous, opportunistic cannibal, the transmission of parasites with either direct or indirect life cycles is possible.

One concern surrounding biological control of an exotic pest is the risk of further reduction of biodiversity, if the target species is eradicated. If gambusia has become integrated into localised habitats, eradication could initiate a perturbation placing further stress on extant aquatic fauna. This concern has been raised in conjunction with rabbit eradication strategies: it has been suggested that, as rabbit populations decline cats and foxes would eat more native fauna.

Gambusia in its native range may be partially controlled by predators including Fundulus spp. However, there are no reports suggesting that, outside its native range, gambusia is other than a minor constituent of the diet of piscivores. On the other hand, it would be interesting to trial the effect of certain exotic predators on gambusia (after ascertaining that such introductions would have no impact on endemic fauna). Some of the larger Cynolebias spp. and Nothobranchius spp. (Cyprinodontiformes) are piscivorous annuals, restricted to seasonal pools, in which they may be able to eliminate gambusia refuge populations. Unmack (unpub. data) and others have observed that gambusia and larger galaxiids rarely coexist and galaxiids eagerly devour gambusia in aquaria. In small waterbodies diadromous galaxiids such as the common galaxiid (Galaxias maculatus) could be introduced at high densities to predate on gambusia, then after 2-4 years the galaxiids would die of old age and since they cannot reproduce in isolated ponds it leaves the waterbody exotic free to reestablish native organisms in.

Arthington & Lloyd (1989) stated that "biological population control is well beyond present capabilities". A decade later, the threat posed by gambusia to the aquatic biodiversity of Australian and New Zealand has not been ameliorated. Further research into predation of native fishes may redefine the problem, and investigation of gambusia-specific parasitism may suggest a solution. Proposals for gambusia control may benefit from knowledge that gambusia is unrelated to native fauna, omnivorous, an opportunist cannibal, and avoids fast-flowing waters. Such schemes may further function as a model system for the eradication of naturalised Tilapia and carp, Cyprinus carpio.

Arthington, A. H. 1991. Ecological and genetic impacts of introduced and translocated freshwater fishes in Australia. Can. J. Aquat. Sci., 48 (Suppl. 1): 33-43.

Arthington, A. H. & L. L. Lloyd. 1989. Introduced poeciliids in Australia and New Zealand. Pp. 333-348, in: G. K. Meffe & F. F. Snelson (eds.), Ecology and evolution of livebearing fishes (Poeciliidae). Prentice Hall, New Jersey, 453 pp.

Barrier, R. F. G. & B. J. Hicks. 1994. Behavioural interactions between black mudfish (Neochanna diversus Stokell, 1949: Galaxiidae) and mosquitofish (Gambusia affinis Baird & Girard, 1854). Ecol. Freshw. Fish, 3: 93-99.

Congdon, B. C. 1994. Characteristics of dispersal in the eastern mosquitofish, Gambusia affinis. J. Fish Biol., 45: 943-952.

Courtenay, W. R. & G. K. Meffe. 1989. Small fishes in strange places: a review of introduced poeciliids. Pp. 319-331, in: G. K. Meffe & F. F. Snelson (eds.), Ecology and evolution of livebearing fishes (Poeciliidae). Prentice Hall, New Jersey, 453 pp.

Crandall, T. A. & P. R. Bowser. 1982. A microsporidian infection in mosquitofish, Gambusia affinis, from Orange County, California. Calif. Fish Game, 68: 59-61.

Diamond, J. M. 1996. A-bombs against amphibians. Nature, 383: 386-7.

Dykova, I. & J. Lom. 1981. Fish coccidia: critical notes on life cycles, classification and pathogenicity. J. Fish Dis., 4: 487-505.

Dykova, I., J. Lom, & R. M. Overstreet. 1994. Myxosporean parasites of the genus Kudoa Meglitsch, 1947 from some Gulf of Mexico fishes: description of two new species and notes on their ultrastructure. Europ. J. Protistol., 30: 316-323.

Fournie, J. W. & R. M. Overstreet. 1994. Host specificity of Calyptospora funduli (Apicomplexa: Calyptsporidae) in atheriniform fishes. J. Parasitol., 79: 720-727.

Gambradt, S. C. & L. B. Kats. 1996. Effect of introduced crayfish and mosquitofish on California newts. Cons. Biol., 10: 1155-1162.

Glover, C. J. M. 1989. Fishes. Pp 89-112, in: W. Zeidler & W. F. Ponder (eds.), Natural History of Dalhousie Springs. South Australian Museum, Adelaide 138 pp.

Haq, S., R. N. Prasad, H. Prasad, R. P. Shukla, & V. P. Sharma. 1992. Gambusia affinis: Dispersal due to floods and its failure to colonize new water bodies in Shajahanpur district (U. P.). Ind. J. Malar., 29: 113-118.

Howe, E., C. Howe, R. Lim, & M. Burchett. 1997. Impact of the introduced poeciliid Gambusia holbrooki (Girard, 1859) on the growth and reproduction of Pseudomugil signifer (Kner, 1865) in Australia. Mar. Freshw. Res., 48: 425-434.

Ivantsoff, W., & Aarn. 1999. Detection of predation on Australian native fishes by Gambusia holbrooki. Mar. Freshwater Res., 50: 467-468

Lom, J. & I. Dykova. 1995. Studies on protozoan parasites of Australian fishes. Notes on coccidian parasites with description of three new species. Sys. Parasitol., 31: 147-156.

Lom, J. , E. J. Noja, & I. Dykova. 1995. Occurrence of a microsporean with characteristics of Glugea anomala in ornamental fish of the family Cyprinodontidae. Dis. aquat. Org., 21: 239-242.

Milton, D. A. & A. H. Arthington. 1982. Reproductive biology of Gambusia affinis holbrooki Baird and Girard, Xiphophorus helleri (Günther) and X. maculatus (Heckel) (Pisces; Poeciliidae) in Queensland, Australia. J. Fish Biol., 23: 23-41.

Minckley, W. L., G. K. Meffe, & D. L. Soltz. Conservation and management of short-lived fishes: the cyprinodontoids. Pp 247-282, in: W. L. Minckley & J. E. Deacon (eds.), Battle Against Extinction: native fish management in the American West. University of Arizona Press, Tucson, 517 pp.

Morgan, L. A. & W. A. Buttemer. 1997. Predation by the non-native fish Gambusia holbrooki on small Litoria aurea and L. dentata tadpoles. Austr. Zool., 30: 143-149.

Nordlie, F. G. & A. Mirandi. 1996. Salinity relationships in a freshwater population of eastern mosquitofish. J. Fish Biol., 49: 1226-1232.

Parenti, L. R. 1981. A phylogenetic and biogeographic analysis of cyprinodontiform fish (Teleostei, Atherinomorpha). Bull. Amer. Mus. Nat. Hist., 168: 335-557.

Perlmutter, A. & H. Potter. 1987. Retrovirus-like particles in embryonic kidney tissue of the platyfish, Xiphophorus maculatus. J. Exp. Zool., 243: 125-135.

Schoenherr, A. A. 1981. The role of competition in the replacement of native fishes by introduced species. Pp. 173-203, in: R. S. Naiman & D. L. Stolz (eds.), Fishes in North American deserts. Wiley, New York, 243 pp.

Segovia Salinas, F., F. Jimenez-Guzman, L. Galaviz-Silva, & E. Ramirez-Bon. 1991. Myxobolus nuevoleonensis, n.sp. (Myxozoa: Myxobolidae) parasite of fishes Poecilia mexicana and P. reticulata from Rio de la Silla near Monterey, Nuevo Leon, Mexico. Rev. Lat-amer. Microbiol., 33: 265-269.

Solangi, S. A. & R. M. Overstreet. 1980. Biology and pathogenesis of the coccidium Eimeria funduli infecting killifishes. J. Parasitol., 66: 513-526.

Unmack, P. 1992. Further observations on the conservation status of the redfinned blue-eye. The Bulletin, 12: 8-9. (Bulletin of the Australian New Guinea Fishes Association, Australia).

Unmack, P. & C. Brumley. 1991. Initial observations on the spawning and conservation status of the redfinned blue-eye, (Scaturiginichthys vermeilipinnis). Fishes of Sahul, 6(4): 282-284. (Journal of the Australian New Guinea Fishes Association, Australia).

Wager, R. 1994. The distribution and status of the red-finned blue eye. Final Report Part B: The distribution of two endangered fish in Queensland. Endangered species unit project number 276.

Wager, R. 1995. Elizabeth Springs goby and Edgbaston goby: distribution and status. Endangered Species Unit Project Number 417. (Final Report).

Wager, R. N. E. & P. J. Unmack. (in prep) Threatened fishes of the world, Scaturiginichthys vermeilipinnis. Envir. Biol. Fishes.

Webb, C. & J. Joss. 1997. Does predation by the fish Gambusia holbrooki (Atheriniformes: Poeciliidae) contribute to declining frog populations? Austr. Zool., 30: 316-324.

Arthington, A. H., P. J. Kailola, D. J. Woodland, & J. M. Zalucki. 1999. Baseline Environmental Data Relevant to an Evaluation of Quarantine Risk Potentially Associated with the Importation to Australia of Ornamental Finfish. Report to the Australian Quarantine and Inspection Service, Department of Agriculture, Fisheries and Forestry, Canberra, ACT.

Arthington, A. H. & C. J. Marshal. 1999. Diet of the exotic mosquitofish, Gambusia holbrooki, in an Australian lake and potential for competition with indigenous fish species. Asian Fisheries Science. 12(1): 1-8.

Brookhouse, N. & Coughran, J. 2010. Exploring the potential for an ecology-specific, physical control method of the exotic pest mosquitofish, Gambusia holbrooki. Ecological Management & Restoration. 11: 226-228.

Cabrera-Guzmán, E., Díaz-Paniagua, C. & Gomez-Mestre, I. 2017. Competitive and predatory interactions between invasive mosquitofish and native larval newts. Biological Invasions. 19: 1449–1460.

Chapman, P. & K. Warburton. 2006. Postflood movements and population connectivity in gambusia (Gambusia holbrooki). Ecology of Freshwater Fish. 15: 357-365.

Cech, J. J. & A. L. Linden. 1987. Comparative larvivorous performances of mosquitofish, Gambusia affinis and juvenile Sacramento blackfish, Orthodon microlepidotus in experimental paddies. Journal of the American Mosquito Control Association 3: 35-41.

Childs, M. R. 2006. Comparison of Gila topminnow and western mosquitofish as biological control agents of mosquitoes. Western North American Naturalist. 66(2): 181-190.

Dove, A. D. M. 2000. Richness patterns in the parasite communities of exotic poeciliid fishes. Parasitology. 120(6): 609-623.

Duncan, D. K. & J. M. Voeltz. 2004. Novel application of a novel tool: using a U.S. Endangered Species Act Safe Harbor Agreement to reduce the use of mosquitofish. Page 70 in Abstract of papers presented at the 13th International Conference on Aquatic Invasive Species, September 20-24, 2004, Ennis, Ireland. 283pp.

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

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

Keller, K. & Brown, C. 2008. Behavioural interactions between the introduced plague minnow Gambusia holbrooki and the vulnerable native Australian ornate rainbowfish Rhadinocentrus ornatus, under experimental conditions. Journal of Fish Biology. 73: 1714-1729.

Komak, S. & M. R. Crossland. 2000. An assessment of the introduced mosquitofish (Gambusia affinis holbrooki) as a predator of eggs, hatchlings and tadpoles of native and non-native anurans. Wildlife Research. 27(2): 185-189.

Laha, M. & H. T. Mattingly. 2007. Ex situ evaluation of impacts of invasive mosquitofish on the imperiled Barrens topminnow. Environmental Biology of Fishes. 78: 1-11.

Lawler, S. P., et al. 1999. Effects of introduced mosquitofish and bullfrogs on the threatened California red-legged frog. Conservation Biology. 13: 613-622.

Macdonald, J. & Z. Tonkin. 2008. A review of the impact of eastern gambusia on native fishes of the Murray-Darling Basin. Arthur Rylah Institute for Environmental Research, Department of Sustainability and Environment, Heidelberg, Victoria. MDBA Publication No. 38/09

McNair, A. Sn., M. Krkosek & S. Nakagawa. 2013. The practicality of Trojan sex chromosomes as a biological control: an agent based model of two highly invasive Gambusia species. Biological Invasions. 15: 1765-1782.

Pyke, G. H. 2005. A review of the biology of Gambusia affinis and G. holbrooki. Reviews in Fish Biology and Fisheries. 15: 339-365.

Pyke, G. H. 2008. Plague minnow or mosquito fish? A review of the biology and impacts of introduced Gambusia species. Annual Review of Ecology, Evolution, and Systematics. 39: 171-191.

Reynolds, S. J. 2009. Impact of the introduced poeciliid Gambusia holbrooki on amphibians in southwestern Australia. Copeia. 2009: 296-302.

Shulse, C. D. & Semlitsch, R. D. 2014. Western mosquitofish (Gambusia affinis) bolster the prevalence and severity of tadpole tail injuries in experimental wetlands. Hydrobiologia, 723:131-144.

Swanson, C., Cech, J.J & Piedrahita, R.H. 1996. Mosquitofish: Biology, Culture, and Use in Mosquito Control. Mosquito and Vector Control Association of California and The University of California Mosquito Research Program. pp. 88.

Willis, K. & N. Ling. 2000. Sensitivities of mosquitofish and black mudfish to a piscicide: could rotenone be used to control mosquitofish in New Zealand wetlands? New Zealand Journal of Zoology. 27(2): 85-91.

NSW, Australia

Centre for Catchment and In-Stream Research (CCISR)
Faculty of Environmental Sciences
Griffith University
Nathan QLD 4111, Australia

Senior Project Scientist
EcoPlan Associates Inc.
701 W. Southern Avenue, Suite 203
Mesa AZ 85210, USA
phone: 480-733-6666 x124
fax: 480-733-6661

Fisheries Biologist
141 N. Bonita, Suite 141
Tucson AZ 85745, USA
phone: 520-670-6144 x236
fax: 520-670-6155
arizonaes.fws.gov

Lloyd Environmental Consultants
PO Box 3014
Syndal VIC 3149, Australia
phone: 03-9884-5559

& Dr. P.K. Gupta
Laboratory of Limnology
Department of Zoology
D.S.B. Campus
Kumaun University, Nainital-263002, India
phone (O): 91-05942-235416

Institute for Applied Ecology
University of Canberra ACT 2617, Australia

An abstract from the Australian Society for Fish Biology 2002 meeting titled density dependent interference competition between Gambusia holbrooki and three Australian native fish.

The Exotic fauna in Western Australian wetlands web page by Mark Lund has two articles on gambusia on their effects on invertebrates in Lake Monger, a lake near Perth in Western Australia. Just click on the Western Australian wetlands and then the exotic fauna link to get to them.

Gambusia affinis fact sheet and Gambusia holbrooki fact sheet from the USGS nonindigenous fish distribution database. Both have good distribution maps for the USA too.

An article from the North American Native Fishes Association journal American Currents on the pros and cons of using gambusia for pest control.

A page from the Illinois-Indiana Sea Grant College Program that reviews aspects of gambusia.

Australia New Guinea Fishes Association

Desert Fishes Council

Desert Springs Action Committee

Native Fish Australia

North American Native Fishes Association

USA Nonindigenous Fish Information Resources