A protective mucous cocoon surrounds this parrotfish as it sleeps in Australia's Great Barrier Reef. This layer of protection helps fend off predators so parrotfish can get a good night's rest.

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to [email protected]. Could you explain how fish sleep? Do they drift ...

Tom has a Master's degree in Journalism. His editorial work covers anything from archaeology and the environment to technology and culture. Tom has a Master's degree in Journalism. His editorial work ...

Do fish with no eyelids sleep? Given that they spend their entire lives submerged in water, this is a reasonable question to ask. Do fish with no eyelids sleep? Given that they spend their entire ...

Contrary to common belief, not all vertebrates regulate their sleep-wake rhythm in the same way. University of Basel researchers have discovered that some fish – unlike humans – do not need orexin to ...