I think aquariums are best seen and appreciated at or near eye level -- possibly below (the coffee table aquarium is one example). I wouldn't put one up there even if I could --- lot of money and special considerations for minimal enjoyment.

If you think crooning up to see the underbellies of your fish or having them lost at the back where the wall blocks them is worthwhile, consult a pro as to appropriateness of the location, size of the tank, cleaning and equipment -- if this is even a possibility. I think you are courting disaster even before you get to feeding think cleaning and other maintenance - which has to be done regularly. But before you even get to that, do you realize how heavy that would be? You are looking at roughly 225 gallons of water -- about 1,800 lbs before adding any rock, glass, etc. I doubt those bookcases and door opening were constructed to support a literal ton of weight. And that much weight in one spot might well require additional support in your foundation. If you get past those hurdles, keep in mind that fish need to be fed, tanks do require cleaning and there will be equipment servicing and other issues. A tiny leak would be a big mess. A tank failure could be a disaster in your home -- and if you file an insurance claim, expect to get your policy cancelled. I think there are better options for aquariums that won't cost as much or have nearly so many pitfalls to worry about.

Essentially, you (others) need to look up to see it and enjoy it. Doesn't seem terribly functional nor like it belongs. Feeding the poor fish a nightmare daily and heat rises as well. Not sure what type of fish, etc. and I'm far from a fish expert. Yet, sounds like a giant chore for something that won't really get appreciated visually.

I cannot think of a worse idea. That thing will be a maintenance nightmare. You must clean fish tanks periodically--not an option. And getting a ladder out every time to feed them? That will get old quickly.

I can't imagine how much the glass will cost that will span 10 feet without breaking. That's going to be expensive.

Are you speaking of a custom fish tank? Made of glass? Above your head?

First of all, you are embarking on an intensive, expensive hobby (unless you plan to pay a service for keeping up the tank). Salt water...fresh water... I wouldn't put a goldfish in a tank that narrow. Goldfish grow to over 12" in a normal lifespan.

Does that room get a lot of natural sunlight? You will have algae--is that what you want? (Some algae isn't necessarily bad for fish, but it's not what most people want inside the public portions of their house).

There are so many things for you to think about a fish tank, the home decorating forum isn't the right place. You should go to a well-reviewed tropical fish store, and start learning about caring for fish. Once you learn a good amount, it will never occur to you to think about putting a tank up over your head.

No not a good idea even assuming the structure would hold the weight. With only a 2 inch gap between celing and tank, how do you propose to do periodic tank cleaning and water changing? Removing and cleaning the pump and filtration equipment and repairing it when it inevitably breaks down? Removing a fish that was sick or deceased? As a pond keeper with several pet fishies Ive had for many years, I assure you there is nothing remotely attractive about a poorly maintained aquarium or pond.... and it would smell.

Why not just continue the arch structure up to the ceiling and finish it off with mouldings? Or have artist design some kind of lighting feature to fit within the space? It could even have fake fish in it to look like an aquarium..... if thats what you want.

OMG - fake aquariums is already a thing! Google fake aquariums.. these artificial jellyfish might be just the thing:

http://www.ebay.com/itm/5x-Glowing-Effect-Artificial-Jellyfish-for-Aquarium-Fish-Tank-Ornament-/332082021957

I swear, I wish I could have my brilliant ideas BEFORE people have already invented them, not after! This isnt the first time....

However I still think that visually it would be unsettling to have a large tank looming overhead whether it has water in it or not.

An aquarium at that height & location is a very BAD idea for too many reasons to list. I would just have that gap closed off, I assume that this is a commercial establishment?

Unless you have unlimited funds, this is not a good idea. Why do you want to put a giant fish tank in that particular spot?

You're just joking, riiiiiight???

Keep in mind too, you're also going to produce a lot of humidity with a tank that size.

You need a plan to deal with controlling that or you could be in future growing some major mold/mildew

No, there has got to be a better place for a fish tank in your home.

Have you figured out how much this thing is going to weigh?

Full, that thing is probably going to weight about 2000 pounds. That's 1 ton. . Can you support that much water?

Acrylic, I assume. And also, no. Lots of reasons.

Here's one: any fish small enough to live in a 10" wide tank will be too diminutive to be seen way up there.

Nice place for a planter perhaps?