Morgan, D.L. and Gill, H.S. (2001) The green swordtail Xiphophorus helleri Heckel (Poeciliidae): another aquarium fish established in the wild in Western Australia. Records of the Western Australian Museum, 20 (3). pp. 349-352.
Considering the enormous number of fish imported into Western Australia each year by the aquarium trade (ca 600 000 individual fish/year from overseas destinations - this figure does not include fish imported from elsewhere in Australia) (W. Cross, personal communication - Australian Quarantine and Inspection Service), it is fortunate that very few species have established wild populations here. Although only a small number of introduced aquarium species, such as tilapia Oreochromis mossambicus (Cichlidae), goldfish Carassius auratus (Cyprinidae), carp Cyprinus carpio (Cyprinidae), one-spot livebearers Phalloceros caudimaculatus (Poeciliidae) and the mosquitofish Gambusia holbrooki (Poeciliidae), are presently entrenched in Western Australian inland waters (Trendall and Johnson, 1981; Allen, 1989; Pen and Potter, 1991; Morgan et al., 1998; Kailola et al., 1999; WA Museum Records; unpublished data), the sheer numbers of these and other species entering the state guarantee an uncertain future. The species mentioned above have either been deliberately or accidentally released into various waterbodies throughout the state and, as this paper highlights, it is probably only a matter of time before other nonnative species establish self-maintaining populations in Western Australia.