English: Octopus cyanea in Kona, Hawaii
Date 2009
Author Brocken Inaglory https://sites.google.com/site/thebrockeninglory/
Source: https://commons.wikimedia.org/wiki/File:Octopus_cyaneain_Kona.jpg

The big blue octopus or day octopus (Octopus cyanea) is an octopus in the family Octopodidae. Octopus cyanea is found on reefs and in shallow waters in the Indo-Pacific. Its range extends from the Red Sea, the East African coast, and Madagascar, to southeastern Asia, Oceania, and as far as Hawaii.