The main issue here is that fish tanks are meant to withstand pressure in a very particular direction. When you put on on its side the new 'bottom' isn't evenly supported on all four side the way the normal bottom is since having the opening in the side leaves the bottom with pressure on three sides not four and the new top being glass and not air is now also in a stressed position being only supported on three sides as well. Does the tank have a 'brace' across the normal top? You might need to strengthen that with a piece of wood up the back of it to add some support to the top piece of glass. Fish tank glass is heavier than reptile tank glass so being unsupported is a greater issue.
For an example if you push down on the top of a glass cup you probably aren't going to break it, lay it on its side and add the same force you can crush it easily.
Even a normal fish tank if the bottom isn't supported evenly all the way around the glass can crack (yup...learned that the hard way).
Reply With Quote