This paper compares eight models predicting the impact of power plant operation upon economically important fish species. The review compares the biological rationale behind model equations; parameter values are tabulated and compared. This paper focuses on differences between the models and the effect of these differences on model predictions. In order to expedite the evaluation of the models, generalized model simulators were developed for the young-of-the-year and life-cycle submodels. Criteria used to evaluate model predictions are percent reduction in young-of-the-year and annual loss in yield to the fishery due to plant operation. Major differences affecting model predictions of these impact criteria include the definition of life stages within age class 0, density-dependent or density-independent mortality for larvae and juveniles, density-dependent or density-independent fishing mortality, and the method for computing recruitment of young-of-the-year fish to age class 1. Major differences in parameter values include entrainment factors, total egg production, equilibrium population size, and survival probabilities for the life cycle models. Recommendations are made regarding our preference between model approaches or parameter values when these differ markedly. A suggestion is made for improved model documentation in the future and for increased cross fertilization of modeling ideas and background data and information.