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

Image: Map of Australia, gold glitter map on dark background
Australia, Tuvalu to launch climate and security pact this yearNews

Australia, Tuvalu to launch climate and security pact this year

by AFP Staff Writers Sydney, Australia - Australia and Tuvalu said Thursday they have agreed to launch a landmark climate and security pact this year, after…
SourceSourceMay 9, 2024 Full article
Satellite Image: flooded areas along the Râul Negru tributary of the river Olt in central Romania
Image of the day: Flooding spreads across central RomaniaNews

Image of the day: Flooding spreads across central Romania

Severe flooding inundated parts of central and northern Romania in late May 2025 after days of continuous rainfall overwhelmed rivers and urban drainage systems. Streets,…
Muser NewsDeskMuser NewsDeskJune 4, 2025 Full article
Oil pumps work rhythmically against the backdrop of dusky sky
US to withdraw from Paris Agreement, expand drillingNews

US to withdraw from Paris Agreement, expand drilling

Washington, United States | AFP President Donald Trump on Monday announced the United States would withdraw from the Paris Agreement for a second time, a…
SourceSourceJanuary 20, 2025 Full article