Median apparent growth rates fell by 17% among openwater species and rose by 12% in the single littoral species studied. Many of the observed changes were large and involved species of commercial or recreational importance (e.g., American shad (Alosa sapidissima), black basses (Micropterus spp.)). The influence of zebra mussels on fish should vary widely across ecosystems as a function of system morphology, factors that limit primary production, and diets of the fish species.