Abstract
Virtual Reality (VR) enables standardised stimuli to invoke behavioural responses in animals, however, in fish studies VR has been limited to either basic 2D visual stimuli for freely-moving individuals or simple 3D stimuli for head-restrained individuals. We developed a novel fully immersive VR setup with 3D scenarios, validated in a proof of concept study on the behaviour of coral reef post-larvae. Larval fish use a variety of cues to select a habitat during recruitment, and to recognize conspecifics and predators, but which visual cues are used remains unknown. We measured behavioural responses of groups of five convict surgeonfish ( Acanthurus triostegus ) to simulations of habitats, static or moving shoals of conspecifics, predators, and non-aggressive heterospecifics. Post-larvae were consistently attracted to virtual corals and conspecifics, but repulsed by their predators. Post-larvae also discriminated between species of similar sizes: they were attracted more to conspecifics than butterflyfish, and repulsed more by predators than parrotfish. The quality of visual simulations was high enough to identify between visual cues – size, body shape, colour pattern – used by post-larval fish in species recognition. Our VR and tracking technologies offer new possibilities to investigate fish behaviour through the quantitative analysis of their physical reactions to highly-controlled scenarios.