There are tens of thousands species of fish around the world, whether it's in an aquarium, river, lake, or ocean. Like all animals (and humans), every single one needs some form of rest for cognitive ...

Researchers have discovered that some fish -- unlike humans -- do not need orexin to stay awake. This molecule was thought to be necessary for normal wake and sleep rhythms in vertebrates. Humans ...

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.