The background actually fits.. it's just not straight in the back. I can get it in there but it fell over.. I pictured my frogs being crushed by it so I said fuggettaboutit.. I am going to try to shave some of the background off in the back then silicone it in. If that does badly, I am going to try tree fern panel or something similar. The false bottom is already installed, I did that part right I think.. lol