Trout predation is listed as a threat to two-spined blackfish Gadopsis bispinosus and Macquarie perch Macquaria australasica. Dietary analysis of 757 rainbow trout Oncorhnychus mykiss and 40 brown trout Salmo trutta for the presence of two threatened fish species was conducted in a tributary & reservoir of the upper Murrumbidgee River catchment, Australian Capital Territory. In general piscivory by trout was low, though increased with size. Predation rate of two-spined blackfish was extraordinarily low, with only five confirmed individuals found. The incidence of predation of two-spined blackfish is surprising given anecdotal evidence that predation was more common. There was no evidence of trout predation upon Macquarie perch. Morphometric analysis of Macquarie perch and goldfish Carassius auratus revealed no significant difference, even though the latter was consumed. The lack of predation on Macquarie perch is most likely attributed to habitat partitioning and behavioural differences between predator and prey. Expansion of a reservoir in the catchment is likely to lead to an increase in the size and abundance of trout as well as an increase in the abundance of Macquarie perch, which may alter the current predator prey relationship between these species.