I'm sure they're asking way too much for him. Bargain with the shopkeep--tell him the octo's only got about a month ahead of him (even if you don't know). If you sound like you know what you're talking about maybe you can get a reasonable price to get him out of that prison.
The tangs are alive. Just stupid. Hippo tangs like to wedge themselves in rocks when they are scared. This tank has no rocks so they are wedging themselves into the corner on the prefilter. Not the best home for them but its only temporary. I was thinking of picking up that octo but I think I am going to wait for one from Octopets.