21.15109/ARP/FDSAC9 Preiszner, Bálint0000-0002-3352-2169(HUN-REN Balaton Limnological Research Institute) ARP 2025 hdl:21.15109/ARP/FDSAC9/4DSIPAhdl:21.15109/ARP/FDSAC9/XPKDV6 The dataset describes laboratory observations of size-dependent scavenging behaviour in black bullhead (Ameiurus melas). It includes activity patterns recorded by video cameras under day and night conditions, comparing different size classes of individuals. The data capture scavenging efficiency and feeding sequences on carcasses of two fish species, common bleak (Alburnus alburnus) and pumpkinseed (Lepomis gibbosus), which differ in body structure. The dataset allows assessment of how body size, time of day, and carcass type influence scavenging activity and efficiency, providing insight into behavioural traits that may contribute to the invasive success of A. melas. Preiszner, Bálint(HUN-REN Balaton Limnological Research Institute)