Like having fish, and giving them a really nice to home live in? Some pet owners are much more enthusiastic than others, so they may want to spend a little extra money to get them something nice. The fish tank condo is a pretty cheap, (but still innovative and awesome looking), fish aquarium for a small number of fish. This is only for if you have a few fish, not dozens for each floor of the condo.
You can also get more Fish Condos, and stack them on top of each other, so that you can have more room for the fish to swim around. This can also be added to an even larger fish tank, just as a decoration, or a little place for your fish to adventure. Buy it quick before they eventually run out of stock!
$35 @ Umbra FishHotel