Feral Animals of the Northern Territory
Gambusia
Family: Poeciliidae
Scientific names: Gambusia holbrooki
Other common names: Mosquito fish, Plague minnow, Guppy
Background
Gambusia was introduced to Australia in the 1920’s to control mosquitoes. For this reason, it has adopted the common name of ‘mosquito fish’. However, its effectiveness in controlling mosquitoes is no greater than that of native fish species. It is now widespread through New South Wales, Victoria and South Australia. Gambusia occurs, but is not common in the Northern Territory.
Feeding
Gambusia has an extremely varied diet, which includes insect larvae, insects, plants, worms, crustaceans, snails, amphibian eggs, fish eggs and small fish.
Breeding
Females reach sexual maturity at four to six weeks of age. Each season, a female may produce over 300 live young, meaning that these populations can grow very rapidly. They have a very high survival rate because they have high tolerances to many environmental conditions.
Impacts
Gambusia is a major pest in Australia. It is highly aggressive and will prey on native fish and amphibian eggs and water bugs. In addition, Gambusia also aggressively competes with native species for food and habitat – nipping at the fins of smaller fish species. For these reasons, the presence of Gambusia has resulted in significant declines in native fish and other species. Gambusia has been linked to the decline of approximately 30 fish species worldwide. Within Australia, Gambusia has been associated with the declines in approximately nine native fish species, and more than ten frog species.
What You Can Do
To prevent further spread and impacts of Gambusia, householders should not keep or release Gambusia to the wild.
