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Introduced species can have profound direct ecological and evolutionary impacts on native species; yet their potential indirect effects remain relatively unexplored. For instance, introduced predators may directly impact some native species via predation, which may in turn have indirect consequences for other natives, for example, by releasing them from competition. We explore this possibility in East Africa’s Lake Victoria basin, where introduction of the predatory Nile perch in the 1950s and 60s contributed to the extinction or extirpation of hundreds of native fishes in the 1980s. We ask whether this dramatic change in community composition has led to competitive release and niche expansion in Rastrineobola argentea, a resilient native cyprinid fish that has thrived in this highly perturbed ecosystem. To address this question, we compare the trophic ecology and morphology of R. argentea before (1966) versus after (2011) the introduction of the Nile perch in Lake Victoria; and across 10 lakes that differ in their Nile perch invasion history. Using this combination of spatial and temporal comparisons, we test for (i) increases in dietary niche breadth (niche expansion),(ii) changes in the level of individual specialization,(iii) changes in trophic position, and/or (iv) changes in trophic morphology of R. argentea in invaded versus uninvaded contexts. In our historical comparison, we find good evidence for dietary niche expansion, an increase in inter-individual diet variation, and an increase in morphological variance in R. argentea following the Nile perch introduction in Lake Victoria. Across lakes; however, strong bottom-up effects (ie, variation in prey …