This is so awesomely disgustingly great I had to post it. There’s a louse that consumes a fish’s tongue and replaces it with itself. Cymothoa exigua was discovered inside the mouth of a red snapper bought from a London market. The louse had grabbed ahold of the tongue and slowly eaten it away until only a stub was left. It then latched onto the stub and became the fish’s tongue — getting a free meal after having fed on the tongue artery while it ate away.
Naturally, some crazy scientists are excited by the find, while the rest of the world remains disgusted. I’m intrigued: it’s certainly a novel idea, and quite frankly, I’m surprised something like this hasn’t been discovered before. The fish most likely came from California, but there is some confusion. Cymothoa was known to exist in the Gulf of California, but since it showed up in London, they’re not sure whether the fish was imported or the louse is simply expanding its territory. Cymothoa poses no danger to humans since it only attaches to fish tongues. Found attached to Lutjanus guttatus (a red or rose-spotted snapper, depending who you read), the parasite poses no danger to humans, but is pretty disgusting.
It enters through the fish’s gills and uses claws to attach itself to the base of the snapper’s tongue and survives by drinking blood from an artery. Once the tongue has been gotten rid of, it attaches itself as a new tongue, and manipulate’s the fish’s food and consumes the free food particles as the fish eats. Again, there is some confusion on what exactly happens: whether the louse eats the tongue, or simply causes it to atrophy due to blood loss, but the net effect is the same: the louse becomes the new tongue.
Imagine dicing up a fish for dinner and seeing one of these little monstrosities, eh? (Another larger image)