My last octo (a pygmy digueti) only died when subjected to having crawled (still never did find out how...clever little bugger) out of his tank, across a 40 foot expanse of carpet, underneath the front door (tight squeeze, too) and almost all the way out the driveway to the street...he was quite old for a pygmy (almost a year) and full of beans...you have to admire his spunk, but it sure was depressing...