Australia has some very well-known invasive freshwater fishes, there have also been non-native marine species detected. For example the Variable Triplefin (Forsterygion varium), a blenny native to New Zealand, has become established in Tasmania after the species was accidentally imported as stowaways in oyster transports. There is also a record of a Striped Beakfish (Oplegnathus fasciatus) caught by a spearfisherman in New South Wales, although as this was a one-off record its unlikely this species has established in Australian waters, but is rather a one-off stray in ballast water from its native range in the northwest Pacific.
Another species from the northwest Pacific, the North Pacific Sea Star (Asterias amurensis) is well-established in Australian temperate waters and its population has reached plague proportions. It has been identified as a factor in the decline of handfish populations, as the star predates both on handfish eggs and the ascidians used as a substrate for laying. Genetic work has identified the source population of these invasive stars as those from Japan - they almost certainly arrived in Australia as larvae in ship's ballast water.
Another species from the northwest Pacific, the North Pacific Sea Star (Asterias amurensis) is well-established in Australian temperate waters and its population has reached plague proportions. It has been identified as a factor in the decline of handfish populations, as the star predates both on handfish eggs and the ascidians used as a substrate for laying. Genetic work has identified the source population of these invasive stars as those from Japan - they almost certainly arrived in Australia as larvae in ship's ballast water.