Potamopyrgus antipodarum is a small snail introduced to Australia and other parts of the world from New Zealand. It occurs widely in south-eastern Australia, but has received scant attention and has not previously been investigated in South Australia. This study had four main components. First, the tolerance of Potamopyrgus to desiccation and high temperature were investigated to determine whether these might limit the species’ range in Australia. Adults and juveniles had an upper thermal limit of 33°C, indicating that high temperatures are likely to limit the northward spread of the species. Tolerance to desiccation was low, as complete mortality in adults occurred in <21h and juveniles succumbed in <30 min. However, conditions in the field may enable this species to survive desiccation longer than these laboratory data suggest. The second component of this study involved an investigation of the hypothesis that low temperatures reduce the growth rate of juveniles and fecundity of adults. Growth rates were near zero at 5°C and significantly higher at 15°C, although the highest rates recorded (maximum 0.29mm month^-1) were much lower than in other studies. No difference was detected between fecundity at 5 and 15°C, and was unexpectedly low overall (0.22 young/individual/week). This result neither supports nor rejects the ‘low temperature’ hypothesis. The third objective of this study originally was to determine the relationship between the population density of Potamopyrgus in Sturt River (South Australia) and the degree of ‘disturbance’. This was diverted by the need to establish a means of obtaining reliable estimates of population density. A technique involving quadrat sampling with an artificial substrate was devised and trialed in a pilot study. This method was found to be efficient, however further work is needed before it can be adopted for a whole river survey. The fourth component considered aspects of the reproductive biology of Potamopyrgus in Sturt River. The male to female ratio of 3.2% indicated that the population reproduces mostly via parthenogenesis, which is typical of invasive populations of this species and consistent with records from eastern Australia. Thirty-five percent of the adult population was infected by parasitic trematodes. This was unexpectedly high, considering that populations in Europe are parasite-free, and only 3.6% of individuals were infected in a Victorian population. A high infection rate is likely to impact on the reproductive capacity and growth rate of the population, as infected individuals may be unable to reproduce. This raises several interesting questions for further study.