Low-Cost Alternative for Examining Social Preference in Zebrafish (Danio rerio) Using the 3-Chamber Open-Tank Free-Swim Task.

Understanding social behavior is a core pursuit in neurobehavioral research, often studied using social preference tasks. These tasks, originally developed for rodents and later adapted for zebrafish, are widely used to examine social dynamics and responses. The 3-chamber open-tank free-swim task (OTFST) consists of a central tank flanked by two stimulus tanks with a camera positioned to record behavior of the subject in the central tank and polarizing film and backlighting to enhance video quality and validity. This protocol uses a low-cost setup with USB webcams and readily available materials. We feature the use of DeepLabCut, an open-source markerless pose estimation tool that enables accurate video tracking of animal movements and provides positional time-series data to be analyzed for various metrics. Pilot sessions validate the system's ability to capture robust social preference behavior. This budget-friendly approach offers an accessible and scalable platform for labs investigating social interaction in zebrafish, and the versatility and relative simplicity of the 3-Chamber OTFST make it suitable for undergraduate teaching laboratories and research projects.