Controversial new research shows that a tiny, unsuspecting species of fish can pass a test that’s widely considered the gold standard of intelligence. As far as we can tell, only a few of the most ...

Bluestreak cleaner wrasse are small, territorial fish that aggressively fend off intruders. But when they have access to a mirror, the fish size themselves up before deciding whether or not to fight.

Jess Thomson is a Newsweek Science Reporter based in London UK. Her focus is reporting on science, technology and healthcare. She has covered weird animal behavior, space news and the impacts of ...

Before deciding whether or not to fight another fish, cleaner wrasse check their own reflection in a mirror and size themselves up. First, Taiga Kobayashi at Osaka Metropolitan University in Japan and ...

Female cleaner fish are sensitive to what their partners can and cannot see while working on client fish. This means they may have theory of mind, a concept built on awareness of other’s perspectives, ...

Cleaner wrasse perform a cleaning service for coral reef fish -- namely eating parasites off their customer's skin. However, what the females of some species actually want is to lure in clients and ...