I know you're set on a different background, but I had one more thought that might make this one work for you if you didn't want to buy another..... when I was trimming mine I got a little sloppy on the sides at one point, so there was just a very small gap. I wasn't worried about my frog getting back there, but my goal was to make it FF proof. I took some of the moss and just plugged that crack up and it completely fixed the issue and kind of looks nice too. I really think that's a cool background you have, but I think a tree look would be good too of course. Just offering up suggestions to make that work for you, or anyone else who might read this and have that issue.