for in side the room et A sweet fish tank, I suggest some ambush preds like a Nandus Nanus, or some other Nandus sp. then put in some bichers like a Ornate fish, maybe a L1140 pleco or a african brown knife? depens on your style, then you can put it in your wall, yes your wall, then you can acess it from the next room over, or closer ext ext depening on how you biuld it, also dont get a petco tank that says here your undergravel filter your tank will be sparkeling clean!
Make a sump, if you dont know how, i can help with that, alo a Cascade canister owuld be a nice add if not Eheim but those are pricey.
The wall idea may be a little out of your leage though, thats allot of work and if your under any kind of lease you prabally cant do it. but you can have it in futuristic cases, my next post will be some links....