This pale little bug is Cymothoa Exigua, also known as the Tongue-Eating Louse, or the Tongue Isopod. They enter through the gills as a juvenile, the Tongue-Eating Louse will clamp on to the base of the fish’s tongue. It uses its claws to sever the blood vessels to the tongue. The tongue falls off after losing blood supply. The Isopod will then take the place of the fish’s tongue, attaching itself to the muscles that controlled the tongue. Probably Hollywood getting idea of Alien type movies from this type of creatures. Therefore, many of bait species like slimy or jack mackerel and yellow tail have them in warmer months.