it is glass dan H
as for a lid i am going to cut a peice of glass to fit right inside there, the glass is purposely down a 1/4 inch so the glass will be counter sunk, and it is going to be a single peice with no joints or hinges and then i will be hanging a light over top, so no traditional canopy. then with a stand that comes up the side of the tank a bit, it will looks like a cube of water sitting there. it is about the closest i will get to a takashi amano style inspired tank, on a real cheap budget hahaha just have to find some riccia, no one seems to have any around here