6 Fascinating Facts About Fish Tongues You Never Knew

Ever bitten into fried cod tongues and thought, “Wait… do fish even have tongues?” Same here.

Turns out they do — but it's nothing like the pink, wiggly thing in your mouth.

Here's the short version, plus a few facts that are honestly kind of unsettling. (Yes, there's a parasite involved. We'll get there.)

So, do fish have tongues?

Yes — but let's set expectations.

What fish have is called a basihyal: a bony structure sitting on the floor of the mouth.

It looks a bit like a tongue. But it's not muscular, it doesn't taste anything, and it definitely doesn't lick.

Instead, the basihyal mostly protects important blood vessels — like the ventral aorta — and in some species helps nudge food or water through the mouth.

Do all fish have them?

Most do — but it varies from species to species.

And here's the wild part: some fish lose their basihyal entirely.

Not to age. Not to injury. To a parasite that replaces it. More on that horror show in a minute.

Wait — what about “cod tongues” on menus?

Here's the plot twist that started this whole rabbit hole (fish tank?) for me.

Those “cod tongues” aren't tongues at all.

They're a tasty muscle from the back of the cod's neck — not the basihyal. So the dish that sparked my curiosity wasn't even the thing I was curious about.

Can fish have teeth on their tongues?

They can — and plenty do.

Certain species have small teeth on the basihyal, usually pointing backward.

These aren't for chewing. They grip prey and push it toward the throat.

Think less “chew toy” and more “conveyor belt with spikes.”

Let's talk about that tongue-eating parasite

Meet Cymothoa exigua, better known as the tongue-eating louse. It's a parasitic isopod, and its life plan is deeply unsettling.

Gross? Absolutely. Fascinating? Also absolutely.

Here's the strange biology: these parasites usually start life as males, then switch to females once they attach.

The good news for the fish — sort of — is that the louse doesn't usually kill its host. But it can make eating and breathing harder, so the fish gets by, just not as comfortably.

Quick answers to common questions