Mosquitofish display differential left- and right-eye use during mirror-image scrutiny and predator-inspection responses

Previous work has shown that predator inspection in mosquitofish, Gambusia holbrooki, is more likely to occur when a mirror image of the test fish is visible on its left rather than on its right side. We investigated whether this is due to a preference for using the right eye when fixating the predator or the left eye when fixating the mirror image, or a combination of both eye preferences. We found that mosquitofish preferentially used the left eye during sustained scrutiny of their mirror image when tested in the absence of any predator. On the other hand, when tested in a swimway for predator inspection responses in the absence of any mirror image (or other social stimuli), mosquitofish explored the environment with the left eye when at a distance and the right eye when near the predator.