Fun Tongue-eating Louse Facts For Kids

Moumita Dutta
Oct 20, 2022 By Moumita Dutta
Originally Published on Nov 01, 2021
Edited by Katherine Cook
Tongue eating louse facts are interesting.
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Age: 3-18
Read time: 5.9 Min

A tongue-eating louse (Cymothoa exigua) is an isopod parasite that latches itself to the tongue of a fish and feeds on the blood vessels of the tongue. It enters the fish's mouth through the gills.

The females attach themselves to the fish's tongue while the males remain attached to the fish's gills.

Once the isopod parasite starts feeding on the fish's tongue, it will not stop until the parasite fully replaces the tongue with isopods. There are more the 380 species of an isopod parasite that attack the mouth of specific fish species.

Once they land inside the mouth of the host fish, it clings to the base of the fish's tongue tightly with the help of their seven pairs of legs. The parasite becomes the functional tongue of the fish from the time they grip onto it.

They release parasitic anticoagulants so that the blood flow does not stop as they grip the fish's tongue very tightly.

The relationship between a fish and the tongue-eating louse parasite can last for years. To know more facts about the parasite, keep on reading the facts on the tongue-eating louse.

For similar content, check out brown marmorated stink bug and ghost ant facts too.

Tongue-Eating Louse Interesting Facts

What type of animal is a tongue-eating louse?

Cymothoa exigua or the tongue-eating louse is a type of tongue-eating parasite found inside the mouth of fish species that replaces the fish's tongue with isopods.

What class of animal does a tongue-eating louse belong to?

The tongue-eating louse (Cymothoa exigua) of the Isopoda order and Cymothoidae family belong to the class of Malacostraca, the biggest class consisting of the largest number of crustacean species.

How many tongue-eating lice are there in the world?

The total number of tongue-eating lice that are present worldwide is unknown. It is a fairly widespread parasite of the marine environment.

This increases the chances of a higher and stable population of tongue-eating lice in the world. Once the parasites enter the fish's mouth, they settle there permanently securing and protecting themselves from other marine threats. The parasite enters the fish's mouth as a male but in due time they change to female as they mature.

However, if more males remain in the gills of the fish, they might climb up to reproduce with the mature female producing more isopods. This further increases the number of parasites.

Where does a tongue-eating louse live?

Tongue-eating lice (Cymothoa exigua) are distributed throughout the parts of the Atlantic. They extend towards the southern part of the Gulf of California up to the northern Gulf of Guayaquil and Ecuador.

What is a tongue-eating louse's habitat?

The tongue-eating louse (Cymothoa exigua) is a marine parasite that lives in a fish's mouth and reaches there by swimming through the gills. They remain attached to the buccal cavity below the tongue. These parasitic creatures mostly populate shallow depths of the sea and are found in the mouth of many marine fish that are commonly eaten by humans.

Who does a tongue-eating louse live with?

The only companion of a tongue-eating louse (Cymothoa exigua) is the host fish to which the isopod attaches itself. Once they find a host, they latch onto the fish's tongue for the rest of their lives and eventually replaces the tongue of the fish.

How long does a tongue-eating louse live?

A tongue-eating louse (Cymothoa exigua) can live up to three years of age.

How do they reproduce?

There is not much information regarding the tongue-eating louse life cycle. The method of reproduction in these parasites is sexual.

The louse starts its life as a male when it attaches itself to the gills of a host. As it grows in size and matures, it turns into a female.

When two male lice are present in the fish's gills, one of them turns itself into a female when they reach 0.4 in (10 mm) in length.

Mating most likely takes place in the gills of the host fish and as soon as it is over, the female moves to the fish's tongue. They carry the eggs in a marsupium-like structure just like kangaroos.

The eggs are released into the water and the juveniles start their life in a water column. As soon as the eggs hatch, this tongue-eating parasite starts to look for a healthy host for attaching themselves.

What is their conservation status?

The species Cymothoa exigua or the tongue-eating louse have a status of Not Evaluated in the Red List produced by the International Union for Conservation of Nature. It is difficult to determine the conservation status of a parasitic species that lives inside the body of another animal.

There is no information about the population of the isopod. However, they are widespread and adapt easily in the mouth of numerous marine fish.

This releases the chances of extinction of tongue-eating louse in the near future. It is common to find a tongue-eating louse in tuna or snapper.

Tongue-Eating Louse Fun Facts

What does a tongue-eating louse look like?

A tongue-eating louse (Cymothoa exigua) is a tiny crustacean resembling other isopods like crabs or lobsters. They are very small in size and are the only known parasite that can entirely replace an organ of its host.

They have seven pairs of legs and use their front claws to constrict the blood vessel of the host in the mouth. Over the course of time, the tongue falls off due to lack of blood and they act as the functional tongue of the fish.

Tongue-Eating Louse inside its host body

How cute are they?

They are not cute, rather they can gross people out.

How do they communicate?

There is no information regarding the communicative behavior of the tongue-eating louse.

How big is a tongue-eating louse?

The length of a tongue-eating louse (Cymothoa exigua) ranges between 0.3-1 in (7.62-25.4 mm). Their length is similar to woodlouse.

How fast can tongue-eating louse move?

The speed with which the juveniles move in water is unknown. The adults, however, settle in the mouth and do not move.

How much does a tongue-eating louse weigh?

The weight of a tongue-eating louse (Cymothoa exigua) is not determined separately.

What are the male and female names of the species?

There are no specific names for male and female lice in this species, both are called tongue-eating lice.

What would you call a baby tongue-eating louse?

A louse in its juvenile stage is called a nymph.

What do they eat?

The tongue-eating louse (Cymothoa exigua) feeds on the blood vessels and mucus of the fish's tongue.

Are they harmful?

They are not harmful to humans but can make a fish weak.

Would they make a good pet?

No, they do not make good pets.

Did you know...

Once a customer found a tongue-eating louse in the mouth of a snapper and filed a lawsuit against the food chain selling them. Later the lawsuit was dismissed as they are not poisonous to humans.

Naming the tongue-eating louse

The tongue-eating louse lives and feeds in the mouth of a fish replacing the fish's tongue due to lack of blood. This is how they get their common name, the tongue-eating louse.

Does the tongue-eating louse kill fish?

A tongue-eating louse or sometimes two can live inside the mouth of a fish, but they do not necessarily kill the fish. However, they can reduce the fish's weight and nutrition by feeding on the host's blood. Sometimes the parasitized fish is observed to even outlive the isopods.

Here at Kidadl, we have carefully created lots of interesting family-friendly animal facts for everyone to discover! For more relatable content, check out these fairyfly facts and stick bug facts for kids.

You can even occupy yourself at home by coloring in one of our free printable pill bug coloring pages.

Second image by Marco Vinci

Tongue-Eating Louse Facts

What Did They Prey On?

Blood vessels

What Type of Animal were they?

Carnivore

Average Litter Size?

N/A

How Much Did They Weigh?

N/A

What habitat Do they Live In?

Inside a fish's mouth

Where Do They Live?

atlantic, south of the Gulf of California, Ecuador, north of the Gulf of Guayaquil

How Long Were They?

0.3-1 in (7.62-25.4 mm)

How Tall Were They?

N/A

Class

Malacostraca

Genus

Cymothoa

Family

Cymothoidae

Scientific Name

Cymothoa exigua

What Do They Look Like?

Small crustacean

Skin Type

Shell

What Are Their Main Threats?

no threats

What is their Conservation Status?

Not Evaluated
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Written by Moumita Dutta

Bachelor of Arts specializing in Journalism and Mass Communication, Postgraduate Diploma in Sports Management

Moumita Dutta picture

Moumita DuttaBachelor of Arts specializing in Journalism and Mass Communication, Postgraduate Diploma in Sports Management

A content writer and editor with a passion for sports, Moumita has honed her skills in producing compelling match reports and stories about sporting heroes. She holds a degree in Journalism and Mass Communication from the Indian Institute of Social Welfare and Business Management, Calcutta University, alongside a postgraduate diploma in Sports Management.

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