These Creepy Little Creatures Live Inside the Mouths of Fish, Replacing Their Tongue

Interestingly enough, this doesn’t kill the fish, since it’s in the parasite’s interest that the fish live as long as possible. As a matter of fact, the fish can even use the louse as a sort of organic tongue prosthesis, that is capable of performing all the duties and functions that a real tongue can – despite being pretty horrifying. So, even though there’s a large isopod living in the fish’s mouth, it can still live a fairly normal life.