High fidelity: Assessing zebrafish (Danio rerio) responses to social stimuli across several levels of realism.

Behavioral assays of zebrafish shoaling have recently been employed to investigate social behavior in zebrafish models of psychiatric disease. Many studies have developed simulated models of conspecifics to serve as alternatives to live shoals in order to examine specific cues that contribute to shoaling behavior. However, no studies have investigated the extent to which zebrafish prefer one stimulus over another when given the choice between two conspecific alternatives (live or simulated). In the present study, we employed a new, four-quadrant choice preference task that allowed zebrafish to swim freely between a live shoal and a motorized mobile shoal, a live shoal and playback of a video-recorded shoal, or a motorized mobile shoal and playback of a video-recorded shoal. Behavior tracking software was used to track subjects' movements in upper and lower quadrants on either side of the test arena. Subjects spent more time near the live shoal, especially in the lower quadrant, and exhibited different swim patterns in response to each simulated conspecific alternative, suggesting that zebrafish prefer a live shoal over models of lower fidelity.