pi_tailtrack: A compact, inexpensive, and open-source behaviour-tracking system for head-restrained zebrafish.

Quantifying animal behavior during microscopy is crucial to associate optically recorded neural activity with behavioural outputs and states. Here I describe an imaging and tracking system for head-restrained larval zebrafish compatible with functional microscopy. This system is based on the Raspberry Pi computer, Pi NoIR camera, and open-source software for the real-time tail segmentation and skeletonization of the zebrafish tail at over 100hz. This allows for precise and long-term analyses of swimming behaviour, that can be related to functional signals recorded in individual neurons. This system offers a simple but performant solution for quantifying the behavior of head-restrained larval zebrafish, which can be built for 340€.