Mosquitofish in Australia

Mosquitofish are considered a noxious pest, especially in New South Wales and Queensland, and it is illegal to release them into the wild or transport them live into any of the states or territories.

[1] Gambusia typically eat zooplankton, beetles, mayflies, caddis flies, mites and other invertebrates; mosquito larvae make up only a small portion of their diet.

[7] They have a resistance to a wide variety of pollutants, including organic waste, heavy metals, insecticides, herbicides, rotenone, phenol, and radiation.

[9] They have also negatively impacted populations of beetles, backswimmers, rotifers, red finned blue eye, Edgbast goby, crustaceans and mollusks, to name a few.

[10] In a study done by Keane et al., 2004, one major threat to Tasmanian fauna could be to native galaxiids, as suggested by the fact that mosquitofish are known to attack and kill adult Galaxias gracilis in New Zealand.

Additionally, Gambusia and other introduced fish may have reduced the suitability of permanent water bodies as breeding sites for pond-breeding amphibian species such as the green and golden bellfrog.

[13] The mosquitofish was nominated as an environmental hazard in NSW in 1999 under the Threatened Species Conservation Act 1995, making it illegal for landowners to do anything that would help spread Gambusia.

[11] In Gordon’s Lagoon at the Clarkesdale Bird Sanctuary in Linton, Victoria, which experiences major infestations of mosquitofish year-round, park managers took advantage of dry conditions by draining ponds in 2008.

[15] In 2018, University of Western Australia researchers built a robot fish that mimics the movements and appearance of the natural predator of the mosquitofish, the largemouth bass, and found that it scared the pest species away.