Strange But True!

by | Sep 8, 2023 | Fish | 0 comments

A new study in February revealed that fish can recognize themselves in photographs! [1]⁣

Dr. Masanori Kohda of Osaka University, the study’s lead author said, “Much like humans, they can look at their face and say, ‘Oh, it’s me!’. It is highly likely that the common beliefs we have had until now will be turned upside down.” [2]⁣

credit: Diego Delso,

⁣The team’s previous studies had shown that Bluestreak cleaner wrasse could pass the mirror test, which measures self-awareness.⁣

In the recent study, cleaner fish demonstrated that they could distinguish their own faces from those of other cleaner fish in photographs, indicating that they remember their self-image. ⁣

These fish are known for their territorialism, and during the study all fish showed aggression towards photographs of unfamiliar fish. However, when they saw photographs of themselves, they did not attack.⁣

The researchers also conducted a photograph mark-test, in which the fish were presented with a picture of themselves with a parasite-like mark on their throat.⁣

Six out of eight fish, when they saw their own picture with the phony parasite, started rubbing their throats like they were trying to clean it off. When presented with photos of their fellow fish with similar marks, they did not attempt to rub their throat.⁣

It is widely believed that animals who have larger brains will be more intelligent than animals with a smaller brain. Dr. Kohda said that it may be time to reconsider this assumption. [3]⁣


[1] M. Kohda et al. Cleaner fish recognize self in a mirror via self-face recognition like humans. Proceedings of the National Academy of Sciences. Published online February 6, 2023. doi: 10.1073/pnas.2208420120.⁣



Thank you to the Biota Group and @justcomics_official for sharing this with us!

  • xeniaforever

    As senior editor here at reefs, I get to work with scientists from all over the world, and have made some wonderful friends in the industry! I also write for the site, and am the office manager at FRESH New London and the mother of two brilliant, talented young women.


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