According to the literature, the occurrence of the decapod Cyrtograpsus angulatus Dana, 1851 (Brachyura, Varunidae), has been reported for the Atlantic Patagonian coast north of 53 degrees S, and along the Pacific coast north of 37 degrees S. The species inhabits muddy bottoms, mainly in estuaries and protected bays. The aim of the present study was to describe the presence of C. angulatus in stomach contents of littoral fishes, i.e., of the species Eleginops maclovinus (Cuvier, 1830) collected in the bay of Puerto Cisnes (44 degrees S, Chile) in the summer of 2017. The results revealed that C. angulatus can be the main or even practically the exclusive prey for E. maclovinus, and can be directly related with individual weight fish. The presence of C. angulatus as a practically exclusive component in the stomach contents of the fish, would indicate that E. maclovinus is an opportunistic predator, and it would apparently predate only on C. angulatus, considering the dominance of the crab in the ecosystem studied.