Be careful when taking it apart. Those types of monitors have big capacitors in them and will still hold a charge long after they have been unpluged from the wall. The discharge from them can cause some serious harm if you do something wrong (ie touch something with your screw driver).
I am an old IT tech and have personally seen people get knocked on their butts from the discharge. Depending on the size of the monitor it can even kill you.
Acrylic would likely be the best material IMHO
to build the inside of the tank with as you can bend it with a heat gun etc to get custom shapes.