Zebrafsh have been demonstrated to react consistently to noxious chemical stimuli and present reliable phenotypes of stress, fear, and anxiety. In this article, we describe the modulation of nociceptive-like responses of zebrafsh to fear-, stress-, and anxiety-eliciting situations. Animals were exposed to an alarm substance, confnement stress, or a novel environment before being injected with 1% acetic acid in the tail. The alarm substance and confnement stress reduced the display of erratic movements and tail-beating behavior elicited by acetic acid. The novelty of the environment, in contrast, increased the frequency of tail-beating behavior. The results suggest that descending modulatory control of nociception exists in zebrafsh, with apparent fear- and stress-induced analgesia and anxiety-induced hyperalgesia.