Just like humans, Betta fish sleep at night. "When sleeping, they become still, with their eyes open because of their absence of eyelids. Betta fish may lose their color while sleeping (it's their ...

You’re staring at your aquarium. It’s late. Everything is quiet. And there’s your fish, floating calmly, fins moving slowly, eyes wide open. Are they... asleep? Or just zoning out? Fish don’t come ...

Emilie Le Beau Lucchesi, Ph.D., is a freelance journalist who regularly contributes to Discover Magazine. She reports on the social sciences, medical history, and new scientific discoveries. View Full ...

Culum Brown does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their ...