As their name suggests, barreleye fish have really weird tubular eyes that they can rotate to gaze upward through their transparent foreheads. Although they appear green, the lenses are actually tinted with a yellow pigment that helps these bizarre fish distinguish between sunlight and bioluminescence.
I thought the same thing! I felt a little better when they explained why it’s awesome further down, being an awesome weirdo is good
The article explained that in the twilight zone (200-1000m down) there’s just enough sunlight filtering through that creatures on the sea floor make shadows, and they’ve evolved bioluminescence to eliminate those shadows, but this fish’s eyes filter out sunlight so that it isn’t fooled. That’s pretty neat!