The European catfish (Silurus glanis) is an emblematic example of an introduced and well-established “megafish” in western and southern European fresh waters. Here, we report how European catfish individuals take advantage of a massive Asian clam (Corbicula fluminea) die-off to feed on dead clams at the water surface during the daytime. This opportunistic feeding behaviour highlights once again the strong adaptation of the European catfish to novel food resource availability, while the species is mainly a nocturnal bottom feeder. This observation also illustrates how feeding bivalves can cause food web alterations through direct benefits to scavenging species.