A common pattern of adaptive diversification in freshwater fishes is the repeated evolution of
elongated open water (limnetic) species and high‐bodied shore (benthic) species from
generalist ancestors. Studies on phenotype‐diet correlations have suggested that
population‐wide individual specialization occurs at an early evolutionary and ecological
stage of divergence and niche partitioning. This variable restricted niche use across
individuals can provide the raw material for earliest stages of sympatric divergence. We …