Putzerfische weisen eine für Säugetiere typische Intelligenz auf: Es wurde festgestellt, dass Putzerfische in Gegenwart ihres eigenen Spiegelbildes kognitive Fähigkeiten aufweisen, die denen von Säugetieren ähneln. Die Ergebnisse deuten darauf hin, dass diese sozialen Fische ein höheres Maß an Intelligenz durchführen können, das als „Kontingenztests“ bekannt ist und bei Delfinen beobachtet wird.

**Cleaner fish show intelligence typical of mammals**

Cleaner wrasse show two hallmarks of self-awareness: speedy self-recognition and contingency testing intelligence

A cleaner wrasse in front of a mirror

**Cleaner fish have been found to exhibit mammal-like cognitive abilities in the presence of their own reflection**.

Researchers at Osaka Metropolitan University in Japan have discovered a previously undiscovered behavior in cleaner wrasse (Labroides dimidiatus). When presented with a mirror, the tiny fish not only recognized themselves, but experimented with the mirror themselves, interacting with it using a scrap of food. The results suggest that these social fish can perform a higher level of intelligence known as ‘contingency testing,’ typically seen in intelligent marine mammals like dolphins.

The group led by Specially Appointed Researcher Shumpei Sogawa and Specially Appointed Professor Masanori Kohda at the Graduate School of Science—who previously showed that wrasse can recognize themselves in photographs—observed the behavior during mirror test experiments. These tests are a common way to test cognition in animals and previous studies have shown that cleaner wrasse recognize themselves in the mirror.

For those interested, here’s the link to the peer reviewed journal article:

https://www.nature.com/articles/s41598-025-25837-0

Cleaner fish being a type of fish that cleans. Not any fish that lives in clean water.