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 onto 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 an idea of Alien type movies from this type of creature. Therefore, many of bait species like slimy or jack mackerel and yellowtail have them in warmer months. Also Read: Sunset Crater of Arizona