Welcome to the Pest Fish in North East Queensland website!
There are at least 20 non-native fishes reported from fresh waters in tropical northern Queensland, eleven of which have established breeding populations. The majority of these species are ornamentals and have ended up in open waters as a result of accidental escape (eg. from garden ponds and farm dams, or use as live bait) or deliberate release (dumping unwanted pet fish).
All of these species potentially can impact local aquatic communities by predation, competition for food and space, or introduction of disease agents such as viruses or parasites to which local species have little or no resistance. At high population density, some species can also cause changes in water quality that may adversely effect sensitive native fishes. This can occur, for example, where bottom feeders stir up sediments that clog gills and cover eggs, or fish increase levels of nitrogen and phosphorus in the water through excretion of their wastes that can trigger plankton or bacterial blooms which create lethal anoxic conditions.
There is still very little information on the ecology of the majority of these fishes in local waters. While a major focus is on the more high profile invasive species, the tilapias, this website is a portal to information on all non-native fishes reported in northern Queensland fresh waters and includes:
Summary fact sheets
Distribution maps (native range and introduced range including in NE Qld)
Photo library to assist species identification
Detailed documents on interesting aspects of ecology/taxonomy of some of the more "notorious" invasive species (especially the tilapias)
