Rapid data acquisition and analysis of behavioral and neural data allow neuroscientists to use real-time events to control experimental parameters. These kinds of closed-loop experiments are important for understanding the relationships between sensory and motor systems in awake behaving animals. Zebrafish are a popular model organism for investigating visuomotor integration and lend themselves well to closed-loop experiments. Bonsai is a powerful and flexible programming language for streaming and analyzing data from multiple sources in real time and has been used in a number of closed-loop paradigms. Until recently, Bonsai did not have modules that were specific to high-speed kinematic tracking in small model organisms like zebrafish. Nicholas Guilbeault and colleagues from the University of Toronto thus developed BonZeb, a suite of Bonsai modules for specifically tracking and analyzing zebrafish movements and integrating these data with closed-loop experiments. BonZeb modules can also be used in an open-loop fashion for collecting, analyzing, and integrating data from multiple sources in real time, or from offline sources for batch processing of pre-recorded data. In their recent publication, the authors highlight several implementations of BonZeb for open-loop single or multi-animal swim tracking; closed-loop optomotor swimming in single or multiple head-fixed zebrafish; and closed-loop optogenetic stimulation experiments. Overall, BonZeb offers great utility and flexibility for small model organism researchers.