Chemical communication is a pervasive and dominant form of communication between animals in aquatic systems. Epidermal-damage-released chemical cues (hereafter referred to as chemical alarm cues or CAC) are typically released during a predation event and, therefore, serve as a reliable indicator of immediate predation risk. Chemical alarm cues are especially useful for species inhabiting aquatic environments when visual cues are limited, e.g. in deep or turbid water, at night, and in complex habitats. By effectively responding to CAC, individuals may increase their probability of survival by detecting and avoiding potential predators, whereas, adopting anti-predator behaviors incurs some cost stemming from concurrent decreases in other fitness-related activities. Since warning communication and reproduction are vital life activities that require high energy consumption, whether the responses of fish to CAC in the breeding season show energy-based trade-offs (cost-benefit) is a scientific issue worthy of attention. However, studies have demonstrated that some species of spawning Ostariophysians seasonally lose their alarm pheromone cells and guarding responses to CAC, and little is known about the relationship between the intensity of behavioral responses of prey to CAC and the physiological state of reproduction. In this study, we used rose bitterling, Rhodeus ocellatus, a small freshwater fish with special reproductive strategies, as an experimental model to investigate the behavioral responses of different genders to CAC during reproductive phase IV, and to determine the role of reproductive physiological status (i.e. gonadosomatic index, oviduct length, and condition factors) in the guarding responses of R. ocellatus to CAC. We defined the behavioral responses of the experimental fish to CAC and divided them into three grades, Grade I:change in spatial distribution in terms of bottom-dwelling time; Grade Ⅱ:change in activity in terms of motionless time, swimming distance, and body fill; and Grade Ⅲ:change in escape behavior in terms of highly mobile time. The results showed that:(1) the spatial distribution (Grade I) and activity (Grades Ⅱ), but not escape behavior (Grade Ⅲ), were significantly affected by CAC (P < 0.05); (2) there was no gender difference in R. ocellatus in response to CAC (P > 0.05); and (3) there was no significant correlation between the behavioral responses to CAC and reproductive physiological status (P > 0.05). We confirmed that R. ocellatus in reproductive phase IV still showed moderate behavioral responses (Grade I and Grade Ⅱ) to CAC. In view of reduced swimming efficiency and increased energy cost in fish during the reproductive period, the non-significant change in escape behavior (Grade Ⅲ) to CAC suggests that there may be energy-based trade-offs (cost-benefit) in this species. Additionally, although the males are brightly colored during the reproductive phase due to sexual selection, it remains to be seen whether the changes in body color increase its predation risk. Overall, moderate behavioral responses to CAC were observed in R. ocellatus in reproductive phase IV, but the intensity of behavioral responses to CAC was not affected by reproductive physiological status and gender. These characteristics are hypothesized to be related to the special reproductive strategies of this species.