I am interested in purchasing an octopus for a pet . i also want to build a suitible habitat. sugg? advice?

octopus are smart creatures. my marine bio teacher used 2 own a pet shop full of fish and he had an octopus. what had happened was that every night the octopus would lift up the top of the tank, walk over to other fish tanks then grab and eat the fish. when my teacher discovered this, he had to put bricks on the top of the tank to the octopus wouldn't eat anymore fish. so my word of advice is if you have a fish tank, make sure your octopus is not able to escape and eat your other fish.