Pelagic copepods in Lake Baikal, Siberia, connect the microbial and classical food webs by eating ciliates, triggering a trophic cascade. The copepod Epischura baikalensis is omnivorous, getting most of its carbon from ciliates and some from diatoms. By consuming mixotrophic ciliates, the copepod boosts biomass transfer to higher trophic levels, potentially increasing fish production. This feeding behavior initiates a three-link predatory cascade, reducing ciliate abundance and increasing growth rates of nanoflagellates. This study suggests that trophic cascades in Lake Baikal need further investigation at larger scales.