The Parasite That Replaces a Fish's Tongue
A small crustacean swims into a fish's mouth, destroys its tongue, and then takes its place, living there as a new tongue for the rest of the fish's life.
What was reported
Cymothoa exigua is a parasitic crustacean, a few centimetres long, found in the eastern Pacific. It enters a fish through the gills, attaches itself to the fish's tongue, and cuts off its blood supply until the tongue withers and falls off.
The parasite then clings to the stump and acts as the fish's tongue, feeding on blood or mucus. The fish can still eat normally. It's the only known parasite that replaces an entire organ of its host.
Explanations offered
The parasite is real and has been studied since the 1700s. It doesn't harm humans, though people have occasionally found one in a fish bought at market, which can be an unpleasant surprise.
- When
- Described in 1783
- Where
- Gulf of California, Mexico
- Witnesses
- Marine biologists and fishermen
- Status
- Confirmed
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.
More from At sea