<p>Mirror self-recognition (MSR) is a method to confirm self-awareness in animals. Recently, it has been documented that small cleaner fish (<i>Labroides dimidiatus</i>) identify their mirror reflection as own image via self-face recognition, suggesting fish have mental image of self-face, and have private self-awareness. Thus, existence of self-awareness will not be restricted to animals of large brain and phylogenetically close to humans. This document will be disproof for main evolutionary models of animal self-awareness: e.g. the gradualist view hypothesis (de Waal, 2019), assuming that large brained animals with phylogenetical closeness to humans would have several levels of self-awareness. This hypothesis is likely to be supported by many researchers including Veit (2023). It is suggested, however, that many studies of MSR would potentially conceive false-negative, and the interpretation of results of MSR-tests that used the traditional mark-test in various animals would misled the evolutionary views of self-awareness in vertebrates. I propose “self-awareness homology hypothesis” that self-awareness in vertebrates will go back to ancestral bony fish in Paleozoic era (450 Mya) at latest.</p>