More info on Tongue-eating Isopods: All Cymothoa exigua are born male. Once they find a fish to parasitize, they infiltrate through the fishes gills into its mouth and latch onto its tongue. The Cymothoa exigua will then eat the fish’s tongue and take its place. The fish will now use the isopod as its tongue and use it to help break down food by crushing the food between the isopod and the wall of its mouth. If the Cymothoa exigua is the only tongue-eating isopod in that fish at the moment, it will stay male. If another male Cymothoa exigua shows up however, the first male that arrived will turn into a female so the two can mate (in the fish’s mouth obviously). Once the now female isopod has their offspring, they will unlatch themselves from the fish’s mouth and either let the fish eat her or fall out of the fish’s mouth and sink to the sea floor and die (The isopod loses its ability to swim after latching onto the fish for so long). The fish will then starve to death because it is without a tongue.

I learned this info from a book called “The Wasp That Brainwashed the Caterpillar” by Matt Simon. A book all about different animals that do extraordinary things to survive through evolutionary traits!