What if that proverbial man in the mirror was a… fish? Would it change its ways? According to an Osaka Metropolitan University-led research group, the answer is yes.

muser Kobayashi
A bluestreak cleaner wrasse (Labroides dimidiatus) swims in a tank at right, with its mirror image at left. Credit: Osaka Metropolitan University

In what researchers describe in Scientific Reports as the first demonstration of a non-human animal possessing certain mental states (e.g., mental body image, standards, intentions, goals), which are elements of private self-awareness, bluestreak cleaner wrasse (Labroides dimidiatus) checked their body size in a mirror before deciding whether to attack fish that were slightly larger or smaller than themselves.

The team – consisting of OMU Graduate School of Science student Taiga Kobayashi, Specially Appointed Professor Masanori Kohda, Professor Satoshi Awata, Specially Appointed Researcher Shumpei Sogawa, and Professor Redouan Bshary of Switzerland’s University of Neuchâtel – was also part of the group that last year reported the cleaner wrasse could recognize photographs of themselves, using their face through mirror self-recognition.

This time, the cleaner wrasse’s behavior of looking into a mirror installed in a tank when necessary suggested that the fish were using the mirror to check their own body size relative to other fish and predict the outcomes of potential fights.

“The results that fish can use the mirror as a tool can help clarify the similarities between human and non-human animal self-awareness and provide important clues to elucidate how self-awareness has evolved,” doctoral candidate Kobayashi declared.

***

This study was financially supported by JST SPRING (JPMJSP2139 to T.K.), JSPS KAKENHI (23KJ1829 to T.K., 19F19713 and 20K20630 to M.K., 22H02703 to S.A., and 20K20154 to S.S.), Swiss Science Foundation (310030_192673 to R.B.), and an OCU Strategic Research Grant 2018–2019 (to M.K. and S.A.).

Journal Reference:
Taiga Kobayashi, Masanori Kohda, Satoshi Awata, Redouan Bshary, Shumpei Sogawa, ‘Cleaner fish with mirror self-recognition capacity precisely realize their body size based on their mental image’, Scientific Reports 14, 20202 (2024). DOI: 10.1038/s41598-024-70138-7

Article Source:
Press Release/Material by Osaka Metropolitan University
Featured image credit: François Libert | Flickr | CC BY-NC-SA

Satellite Image: Atlantic Ocean (s. Storm Leonardo)
Image of the day: Storm Leonardo advances across the Atlantic toward IberiaNews

Image of the day: Storm Leonardo advances across the Atlantic toward Iberia

Successive Atlantic storms left little time for recovery across parts of Spain and Portugal in early February 2026. After flooding and coastal impacts linked to…
Muser NewsDeskMuser NewsDeskFebruary 7, 2026 Full article
Satellite Image: The Ganges River, India
Image of the day: Ganges River in eastern IndiaNews

Image of the day: Ganges River in eastern India

Stretching more than 2,500 kilometres from the Himalayas to the Bay of Bengal, the Ganges River anchors one of the world’s most densely inhabited and…
Muser NewsDeskMuser NewsDeskNovember 16, 2025 Full article
Image
Experts, activists slam ‘pointless’ G7 on climateNews

Experts, activists slam ‘pointless’ G7 on climate

By Ella IDE | AFP Bari, Italy - The Group of Seven rich democracies have failed to deliver significant new progress on climate during a…
SourceSourceJune 14, 2024 Full article