A blue-green octopus with long arms and deep webbing, hunting at night by throwing the web over a coral head and feeling underneath it.
To about 60 cm overall, blue-green with long arms and deep webbing between them, and skin that raises into papillae when the animal is alert. The colour is the character most divers remember, and it is unusual among octopuses for being consistently green rather than brown.
It is nocturnal and hunts by parachuting: it spreads the web over a coral head and feels underneath it with the arm tips, taking crabs and small fish it never sees. A night dive over shallow reef is the way to find one, and the animal will often carry on hunting with a light on it if the light is kept off the eyes. Dens are marked by a pile of shell and crab debris outside the entrance, which is the way to find one by day. It lives about a year, breeds once and dies, which is normal for an octopus and still surprising for an animal that intelligent.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.
