NSW DPI is involved in several aquatic habitat rehabilitation projects funded by local, state or federal bodies including councils, the former Catchment Management Authorities (now Local Land Services), and the Murray-Darling Basin Authority. Protection and restoration of fish habitats through aquatic habitat rehabilitation can help to tip the balance in favour of native fish and away from introduced pest fish. This improves the ability of native fish to compete and creates conditions less suitable for introduced pest species. Management of issues such as water quality, environmental flows, fish passage and snags can maintain or return conditions to those that best suit native fish. However, there are some options for pest fish management and improving the odds for native fish.Įnvironmental management and aquatic habitat rehabilitation. Well-established introduced aquatic species are difficult to control. However, there has been one recorded outbreak of the disease in a silver perch fish farm in NSW. NSW DPI researchers have found that fingerlings of Murray cod, golden perch and silver perch are resistant to GUD. Since then, outbreaks have occurred at warm water fish hatcheries in NSW and Victoria. Goldfish ulcer disease (GUD) is a bacterial disease first isolated from a goldfish farm in Victoria in 1974. One impact that has been well recorded is the transmission of disease. Few detrimental effects have been recorded, however, this may be due to limited research. Impacts on native fishĭespite being related to carp, little is known about the impact goldfish have on native fish, particularly regarding the competition for food, resources and habitat. Goldfish are commonly up to 200 mm in size but can reach 400 mm. Observations made by DPI research staff suggest that goldfish can be a food source for some predatory freshwater fish such as Murray cod. A large fish can lay several hundred eggs which hatch in about a week. They survive in still and sluggish water and can tolerate relatively high temperatures and low oxygen levels. ![]() Goldfish are related to carp (both from the Cyprinidae family) and feed mostly on small shellfish and plant material. ![]() Over many decades they have become widely distributed throughout lowland rivers. Goldfish were originally imported into NSW as a colourful and easy to maintain coldwater aquarium fish.
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