Dominant eye-dependent lateralized behavior in the scale-eating cichlid fish, Perissodus microlepis.

Visual lateralization, which is commonly observed in many animals, is believed to influence behavioral choices or lateral biases; however, the underlying mechanisms remain obscure. In the present study, we examined eye dominance in the scale-eating cichlid fish, Perissodus microlepis, and the role of the dominant eye in lateralized predation. P. microlepis responded to visual stimuli at a significantly higher rate when applied to the eye on the mouth-opening side than to the other eye, revealing visual lateralization. Impaired dominant eye vision with artificial cataracts reduced attacks from the dominant side, halved body flexion angle velocity, and significantly lowered predation success, demonstrating the role of the dominant eye in attack direction and performance. These findings reveal that P. microlepis has clear visual lateralization, which can be used effectively for side attacks during scale eating, probably with relatively high visual acuity or an efficient visual system, providing significant foraging advantages.