UPDATED: 9.46AM Inky the Octopus has slithered through a drainage pipe at the National Aquarium in Napier, and escaped to the ocean.

One of two octopuses in residence at the aquarium, Inky would have had to make a slippery dash across the floor and squeezed himself down a 150 millimetre pipe.

It's the first escape ever from the Marine Parade attraction.

Aquarium manager Rob Yarrall said while they'll miss him, it's likely he's found love, and won't be returning.

"Once back out to sea he would have headed off towards the reef and that would be his life. He would be quite happy out there. We wouldn't go try and track him down."

He said he's probably returned to Pania Reef where he was rescued two years ago after becoming caught in a fisherman's net.

Yarrall said it's most unusual, and the remaining octopus is under close observation.

He said like all octopuses, Inky had been relatively reclusive and enjoyed his seclusion, despite sharing the enclosure with a companion.

He would also have been inquisitive, and would have taken in his surroundings closely - too closely. They included a small gap at the top of his home, through which he squeezed.