He LIVES!
Dean has been interested in keeping an octopus for years. Our first, from a couple years ago died in our "Death Camp" tank where Dean was mis-measuring iodide for several weeks creating toxic water that killed hundreds of dollars worth of fish.
This last month we moved all of our fish into the 90-gallon to clear out room for an octopus in the 30-gallon. Octopus #1 made it one night. Octopus #2 made it one night. And then finally after swapping out ALL of the water with old, well-cycled water from the store, Octopus #3 has made it 4 days. They're such sensitive creatures that if the water quality is poor (even too new of water in a well-established tank is bad) they'll just die right away - so this is a good sign. Dean was so disappointed with the first two that I didn't even want to try again, but I gave in.
I'm glad I did. He's pretty cool. He's active and comes out to see us for a couple hours each day. He won't take the food we've been giving him (not that we can see at least). But plenty of the hermit crabs are turning into shells only - so I think he's doing okay there. He's also created a little cave for himself and he will use his tentacles to pull in rocks and shells to board it up at night when the lights go out.
Anyway, here are a few pics: