An extraordinary variety of pharmaceutical pollutants (e.g. medications like antidepressants and painkillers) now contaminates most major rivers, lakes, and seas around the world. Under artificial laboratory conditions, exposure to pharmaceuticals can change animal physiology and behaviour at ecologically relevant concentrations, but how these results translate in complex natural systems remains unknown. Further, we know next to nothing about whether and how exposure to pharmaceuticals influences species interactions. In this study, we combined acoustic telemetry and biologging technology, with targeted exposure implants, to track the behaviour of multiple fish species that were either exposed or unexposed to a mixture of pharmaceutical pollutants. We tracked the fishes’ movement, behaviour, and interactions for 40 days across three natural, but highly standardized, experimental lakes. Each lake was stocked with 30 roach (Rutilus rutilus) and 30 perch (Perca fluviatilis) as prey species, and six northern pike (Esox lucius) as predatory species. Before releasing fish into the lakes, we surgically inserted an acoustic transmitter tag into each fish as well as a specially designed slow-release pharmaceutical implant, which contained either a mixture of three pharmaceuticals (fluoxetine, sertraline and venlafaxine; 25ug\L of each drug) or a control implant. These slow-release implants allowed us to chronically expose the study animals across the entire experimental timeframe and to examine the consequences for their movement, behaviour, and interactions (including predator-prey interactions). We also surgically implanted pike with a centi-HRT ACT tag to monitor predator heart rate activity and body temperature throughout the experiment. I will discuss our preliminary findings and more broadly talk about the extraordinary power, but currently unfulfilled potential, of using animal tracking technology for exploring the impacts of environmental pollution on the spatial and temporal dynamics of animal behaviour in natural systems.