A bioeconomic model of reservoir aquaculture in northern Vietnam is used to investigate the impacts of price and yield risk on the level, variability and skewness of expected net revenue and utility. Prices and yields are assumed to follow lognormal and beta distributions, respectively. Net revenue follows a generalized gamma distribution and is found to be very risky compared with similar enterprises elsewhere, mainly due to the relatively high yield risk. This represents the nascent nature of the industry in Vietnam and the opportunity for efficiency improvements. Increasing production capacity (through increasing reservoir size, stocking density, production cycle length and harvest rate) are found to increase profits and decrease the variability of profits. Species diversification was found to reduce the riskiness of the enterprise.