Association of predation risk with a heterospecific vocalization by an anabantoid fish.

Honey gouramis (Trichogaster chuna) received chemical alarm cues derived from conspecific epidermal tissue and, simultaneously, the vocalization produced by a heterospecific gourami species, the sparkling pygmy gourami (Trichopsis pumila). Control trials paired water with the vocalization. In trials that received alarm cues, honey gouramis significantly increased activity relative to control trials that received water, suggesting an attempt to flee and search for refuge. When the recording of the vocalization was later replayed to test fish without any additional chemical cue, fish that had previously experienced the alarm cue froze while those that had received water with the vocalization did not change their behaviour. These data indicate that honey gouramis recognize and respond to chemical alarm cues, making this report the second anabantoid species to be recorded with this response. Second, these data indicate that honey gouramis can associate risk of predation with a novel auditory stimulus, including vocalizations from other species. These data suggest the potential for vocalizations to evolve into alarm signals in this group of fishes.