This creepy tongue-eating 'vampire' is a fish's worst nightmare
Get a closer look at the blood-sucking parasite that eats, and then replaces, a fish's tongue without it knowing.
This "vampire" crustacean (in purple) eats and then replaces the fish's tongue.
Fish don't have the easiest lives. They have to avoid predators, fishing nets, pollution and now vampire crustaceans that want to eat their tongues.
The tongue-eating louse will invade a fish's mouth, then suck the blood from the fish's tongue until the tongue completely fades away. Then the parasite replaces the tongue itself.
Rice University biologist Kory Evans discovered the creepy tongue biter while digitizing X-rays of fish skeletons. "These parasites attach themselves to the tongues of fishes and effectively become the new tongue ... horrifying," Evans tweeted on Monday.
Mondays aren't usually this eventful. I found a tongue-eating isopod (purple) in one of our wrasse scans this morning while digitizing it. These parasites attach themselves to the tongues of fishes and effectively become the new tongue...horrifying #backdatwrasseup pic.twitter.com/axlraUrh8W
— Kory Evans PhD (@Sternarchella) August 10, 2020
This particular parasite was discovered in a wrasse, a herring cale, found in New Zealand when Evans was working on a 3D X-ray database of skeletal morphology of coral reef fishes.
"It looked like it had some kind of insect in its mouth," Evans told Live Science on Wednesday. "Then I thought, wait a minute, this fish is an herbivore, it eats seaweed. So I pulled up the original scan, and lo and behold, it was a tongue-eating louse."
There are around 380 species of tongue-eating isopods in existence. The isopod enters a fish's body through the gills, grabs onto the fish tongue with its legs, and feeds on it until the tongue withers away. The devious isopod is extra efficient in that it uses an anticoagulant to keep the blood from clotting.
Once the tongue has disappeared, the isopod's body acts as the fish's tongue, living off the fish's mucus. However, while the parasite replaces the fish's tongue, that doesn't mean the fish is doomed to die.
"Parasites can remain attached to the fish for several years, grow as the fish grows and then become detached," Stefanie Kaiser, from New Zealand's National Institute of Water and Atmospheric Research, told the American Association for the Advancement of Science in 2012. "There are, in fact, many examples of fishes outliving their isopod parasites."
