---
title: "Cleaner wrasse · Animals and other organisms · Entities · Simulation Hypothesis"
url: https://simulation-hypothesis.com/entities/wrasse
description: "A reef fish that passed a version of the mirror mark test. People disagree about what that shows."
license: https://creativecommons.org/licenses/by/4.0/
credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)"
---

[Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Fish and amphibians

# Cleaner wrasse

Labroides dimidiatus

A reef fish that passed a version of the mirror mark test. People disagree about what that shows.

Neurons

No published count

## Evidence

* It passed the mirror mark test: it reacted to a coloured mark visible only in its reflection. How to interpret that is debated.  
Kohda M, Hotta T, Takeyama T, Awata S, et al. (2019) If a fish can pass the mark test, what are the implications for consciousness and self-awareness testing in animals? PLoS Biol 17(2):e3000021\. doi:10.1371/journal.pbio.3000021.

The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds at least a realistic possibility of conscious experience in all vertebrates and in many invertebrates, including cephalopods, decapod crustaceans and insects.

Assess it against the published criteria