This study examined rational behavior-control method of pointhead flounder (Cleisthenes herzensteini), slime flounder (Microstomus achne), and red halibut (Hippoglossoides dubius) based on a morphological study of their brains. The specimens were sacrificed and the brains removed. Based on brain morphology, we classified these species as of the ‘plaice type’. These species have a large tectum opticum, which suggests that vision is the most important sense governing behavior,based on external stimulation. The olfactory bulb was more developed in the pointhead flounder than the slime flounder and the red halibut, implying the importance of olfaction in the pointhead flounder. We postulate that form vision is more important than motion vision based on the large cerebellum in these species. We conclude that these species have superior vision, and postulate that their visual acuity is important in their behavior. Therefore, we hypothesize that the form of fishing gear is important, and behaviorcontrol techniques that use visual stimuli should be effective in fishing targeting the pointhead flounder, slime flounder, and red halibut.