Is it true that the Barreleye normally points those eyes straight up, watching for prey silhouetted against the faint light above?

Yes — the Barreleye normally points those eyes straight up, watching for prey silhouetted against the faint light above.

Is it true that the Barreleye rotates its eyes forward inside the transparent skull when it feeds, so it can watch its food while it eats?

Yes — the Barreleye rotates its eyes forward inside the transparent skull when it feeds, so it can watch its food while it eats.

Is it true that the Barreleye has two dark spots above its mouth that look like eyes but are really its nostrils, while the glowing green orbs inside the clear dome are its actual eyes?

Yes — the Barreleye has two dark spots above its mouth that look like eyes but are really its nostrils, while the glowing green orbs inside the clear dome are its actual eyes.

The fish with a transparent head and eyes that rotate inside it

Q: Is it true that the Barreleye has a whole forehead made of a clear fluid-filled dome, so you can look straight into its skull?

Yes — the Barreleye has a whole forehead made of a clear fluid-filled dome, so you can look straight into its skull.

Q: Is it true that the Barreleye keeps its real eyes inside that dome as two barrel-shaped tubes?

Yes — the Barreleye keeps its real eyes inside that dome as two barrel-shaped tubes.

The short version

The barreleye lives ~800m down and has a transparent fluid-filled dome for a forehead. The two green domes people mistake for eyes are its nostrils; the actual eyes are barrel-shaped tubes inside the skull that normally point straight up and rotate forward when it feeds.

Why it's so weird

✓The Barreleye has a whole forehead made of a clear fluid-filled dome, so you can look straight into its skull.
✓The Barreleye keeps its real eyes inside that dome as two barrel-shaped tubes.
✓The Barreleye normally points those eyes straight up, watching for silhouetted against the faint light above.
✓The Barreleye rotates its eyes forward inside the skull when it feeds, so it can watch its food while it eats.
✓The Barreleye has two dark spots above its mouth that look like eyes but are really its nostrils, while the glowing green orbs inside the clear dome are its actual eyes.

📏 How big is it, really?

Barreleye

15 cm

a 7-year-old

1.2 m

🧒

You could line up about 8 of them along a 7-year-old!

The full story

This fish has a completely transparent head, and its eyes are inside it. Meet the barreleye, which lives around eight hundred metres down in the Pacific. For decades every specimen hauled up in a net arrived destroyed, so nobody realised what they were even looking at. Then in 2004 scientists finally filmed a living one, and found that its whole forehead is a clear fluid-filled dome. Those two glowing green domes are not its eyes. They are its nostrils. The real eyes are the two barrel-shaped tubes inside the head, and they normally point straight up, watching for prey silhouetted above. When it finds something, the eyes rotate forward inside the transparent skull, so it can watch its food while it eats. Follow for more weird animal facts.

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