Data for - Increasing Group size and Multi-cue Environment impact Decision-Making in Wild Zebrafish

Social animals often seek to maintain a group in order make the highest benefits of group living while minimizing the drawbacks. To maintain a group properly, it is crucial for the group members to reach a consensus. Group size and the environmental context, including its components and complexity, substantially influence decision-making. Therefore, we explored the combined roles of increasing group size and environmental context on decision-making of individuals in wild zebrafish (Danio rerio). We exposed solitary individuals, pairs, and shoals of 6, 10, or 14 members to multi-cue environments comprised of visual and olfactory cues from predator, vegetation, and food. In our study, we considered four behavioral metrics to gain insight into the speed of decision-making, boldness and the success of foraging attempts. Shoals were faster in making decisions and bolder than solitary fish and pairs but achieved a plateau when a critical group size was reached. Solitary individuals made the highest number of successful foraging attempts. Interestingly, individuals of medium-sized shoals (N = 6 and 10) were the quickest and boldest while making the first successful foraging decision compared to any other group. When vegetation was present, individuals were reluctant to leave the refuge even for food regardless of the presence of the predator. However, the predator cues did not make any strong additional change in their decision-making. Our study reveals possible optimal group size to maintain both high speed of decision making and foraging success as well as signals the importance of vegetation as shelter for wild zebrafish.