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.

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 ...

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 ...