Inky the octopus escaped from the National Aquarium in Napier, New Zealand, in January, but the news is just now being released (video below).
The male octopus, which is about the size of a rugby ball, made its escape through a small pipe, notes Stuff.co.nz.
The aquarium staff noticed that there were octopus tracks that led from a small opening at the top of Inky's tank across a wet floor.
Inky is believed to have made his way into a drain that led to the Pacific Ocean, where the escapee is likely now residing.
Inky began living at the aquarium in 2014 after a fisherman and aquarium volunteer rescued him from a crayfish pot, which are normally used to catch shellfish.
Inky was fed fish three times a week at the aquarium but will now have to make due on his own.
Aquarium manager Rob Yarrall told Radionz.co.nz:
Octopus, in general, are incredible escape artists. They can fit through very, very small spaces, even quite a large octopus. They can squeeze down to the size of their mouth, which is the only really hard part of their body, it's a beak, very much like a parrot beak. So this particular day, maintenance work had been carried out, and the lid had been left just slightly ajar, just slightly.
"He managed to make his way to one of the drain holes that go back to the ocean and off he went and didn't even leave us a message, he just off and went," Yarrall later added.
The aquarium still has a second octopus who shared Inky's tank.
Yarrall told Hawke's Bay Today that Inky's getaway was the first escape he that has ever reported,.
"Yes, it's most unusual and yes, we'll be watching the other one," he added.