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The Horrifying Tongue Eating Louse

Updated on July 8, 2014


The tongue eating louse (Cymothoa exigua) is a horrifying parasitic isopod that pretty much does what its common name suggests. It attaches itself to the base of the host's tongue and gradually eats it, until there is nothing left. And talking about hosts, you have no reason to be afraid of it. The species only parasitizes on a handful of fish species.

After finishing the job, Cymothoa exigua attaches itself to the stub of what used to be the tongue and becomes the fish's new tongue. Scientists say that infected fish even try to use the parasite as if it was their natural tongue, albeit with not much success.

As of today, the tongue eating louse remains the only known parasite that actually "replaces" a host's organ with itself. Surely, it deserves a place in the catalog of the world's most strange parasites.

The tongue eating louse replaces the host's tongue with...itself !
The tongue eating louse replaces the host's tongue with...itself !

Distribution and hosts

The tongue eating louse has a widespread distribution, with specimens having been collected from the Gulf of California south to north of the Gulf of Guayaquil, Ecuador.

Cymothoa exigua has been reported to parasitize a total of 8 fish species, from two orders and four families.

1) 7 species of the order Perciformes:

  • 3 snappers (Family: Lutjanidae)
  • 1 grunt (Family: Haemulidae)
  • 3 drums (Family: Sciaenidae)

2) And one species of order Atheriniformes, an Atherinidae grunion.

Video showing a tongue eating louse that has been removed from its host. According to the caption, it was shot in Freeport, Texas, in 2009.


The parasite begins its lifecycle by entering the host through the gills. Usually, more than one individuals enter the victim. There, one female uses its front claws to take grab of the tongue's base, whereas the males attach either right behind her or on the gills.

The female then starts to suck blood, causing the tongue atrophy and eventually to drop off. Once the tongue is dropped, the female reattaches to the tongue stub, effectively becoming a new "tongue". As for males, they either feed directly from the host's blood or on fish mucus

Interestingly, other than losing a tongue, the infected fish appear to suffer little damage from the infestation. To quote a researcher, “C. exigua appears to be a benign parasite whose influence could modify the behavior of heavily parasitized fishes, the effect can be considered insignificant at the present time.”


The exact reproductive mechanisms of the tongue eating louse still remain a mystery. However, we know that each female lays 480 to 700 eggs, which are released into the ocean.

Sometimes, a fish is only infected by male individuals. Still, this is no problem for this hideous creature. In the absence of females, a male can change sex and turn into female, thus ensuring breeding will take place.

Relationship with humans

As aforementioned, the tongue eating louse only parasitizes on a small range of species. It does not eat human tongues, although live individuals are quite vicious, delivering a nasty and painful bite. Treat live specimen with care!

Video showing a couple removing multiple individuals from a dead fish.

More strange anmals and parasites !

I hope you enjoyed reading about this creepy little creature. If you did, please consider sharing and liking my hub :)

You may also want to check the following links, featuring some other crazy and strange animals:

Gimme a kiss ! No? Ok :(
Gimme a kiss ! No? Ok :(


Submit a Comment

  • fildi profile image

    Karl 4 years ago from United Kingdom

    Could this louse be inspiration for Alien?

  • Vicki.Pierce profile image

    Susan Ungrey 6 years ago from Grand Rapids, Michigan

    Well welcome to hubpages! Glad I could make you happy!

  • Kofantom profile image

    Kofantom 6 years ago

    yeah I know :)..Thanks for commenting btw ..I am just starting with hubs and stuff so seeing people commenting makes me really happy :P

  • Vicki.Pierce profile image

    Susan Ungrey 6 years ago from Grand Rapids, Michigan

    Ewwwwwww! That is crazy! Never heard of such a thing! Thanks for sharing!