Goldfish
Carassius auratus
Widely distributed by acclimatisation societies in the 1870s, probably first introduced in the 1860s. Their spread has been assisted by anglers using goldfish for live bait.
Now form part of the food chain as forage fish for larger natives such as Murray cod and golden perch.
Known to hybridise in the wild with carp producing offspring of mixed characteristics.
Will take a hook, but provides poor sport and the flesh is of poor edible quality.