Understanding fear generalization in adult zebrafish in predator-based assays

Critical for behavioral adaptations to various natural threats, fear and its generalization have been extensively studied in mammals, including rodents and primates. The zebrafish (Danio rerio) represents a promising model organism for studying neurobiological bases of emotions and cognitions. Although fear generalization is critical for organismal survival, it remains poorly understood in zebrafish. To address this problem, here we applied a natural predator (Indian leaf fish, Nandus nandus) exposure in various contexts to systematically probe zebrafish behavioral strategies following this vital threat. Overall, our experiments show that zebrafish remember past exposure to a live predator and can generalize this information by avoiding both current and prior locations of the predator in the exposure tank. Collectively, this confirms that zebrafish are capable of generalizing predator fear, and employ advanced cognitive processes (similar to those observed in mammals) in their behavioral strategies when exposed to vital threats.