You've probably heard of the saying "a cat got your tongue," but have you ever heard of a parasite eating and becoming a fish's tongue.

According to San Antonio ABC station KSAT, authorities with the Texas Parks and Wildlife Department got a snapshot of a bizarre parasite that looks like a pill insect and is also known as the snapper-choking isopod.

Galveston Island State Park was where the parasite-carrying fish was discovered. Before providing the real science underlying the crustacean, officials joked on Facebook that the critter was a Martian.

According to the Houston Chronicle, the tongue-eating louse attaches itself to the fish's mouth and subsequently replaces the tongue.

The parasite then feeds on the host animal's mucus in the fish's mouth, the only known instance of a parasite replacing an organ of its host.

Although the tongue-eating louse's method of operation may seem terrifying, authorities claimed in a Facebook post that the critter "does not harm the fish or damage humans."

So far, one person's reaction to the scary monster may be summarized as follows: "Thanks for the additional nightmare fodder." The old monsters were starting to bore me."

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Tongue-Eating Louse (Cymothoa exigua)

Cymothoa exigua
(Photo : Wikimedia Commons)

The tongue-eating louse, Cymothoa exigua, is a parasitic isopod belonging to the Cymothoidae family. It enters fish through the gills, with the female adhering to the tongue and the male attaching beneath and behind the female on the gill arches. Females have a length of 8-29 mm (0.3-1.1 in) and a width of 4-14 mm (0.16-0.55 in). Males have a length of 7.5-15 mm (0.3-0.6 in) and a width of 3-7 mm (0.12-0.28 in).

The parasite causes the fish's tongue to fall out by severing the blood vessels in the tongue. It subsequently joins the remaining stub of the fish's tongue and forms the fish's new tongue.

The horrific stowaway was discovered when scientists X-rayed a fish's head recently: the "vampire" crustacean had consumed, then replaced, its host's tongue.

The Parasite's Behavior

While scanning X-rays of fish bones, biologist Kory Evans, an assistant professor in Rice University's Department of BioSciences in Houston, Texas, found the tongue biter. On Aug. 10, he posted photos of the startling and terrifying discovery on Twitter: In the tweet, Evans joked, "Mondays aren't typically this exciting."

The bug-like isopod, commonly known as a tongue biter or tongue-eating louse, feeds on a fish's blood until the entire structure withers away. The ultimate tragedy starts when the parasite takes the organ's place in the mouth of the still-living fish.

Will they infect people?

Cymothoa exigua
(Photo : Wikimedia Commons)

According to Evans of, they primarily feed on salty game fish, such as snappers, and do not injure the fish other than replacing its tongue. However, multiple parasites may cling to the tongue, causing the host fish to become underweight owing to a lack of food.

Aside from the visceral reaction to hearing the phrase "tongue-eating lice," it's nothing to be concerned about for humans. It is, however, an interesting insight into our aquatic companions.

"They're nothing to worry about for the fish or humans," he added.

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