The tank looks good but like you already stated a background is needed. I've used a drop in background with great success. And with your tank already set up it is easy to do.
If you're interested:
Pick up a 1/4" pink insulation board.
Take a good measurement of the the back of the tank (Inside).
Cut the board to the exact dimensions.
Check the board for a snug fit.
Remove the board so you can work on it outside the tank.
Great Stuff what ever you want on the pink board (including wood, plant cups, etc).
After the great stuff dries coat the entire surface with "brown" silicone and press in what ever material you like. (I prefer peat moss)
After the silicone dries turn the board upside down and shake off the excess peat. Fill in any bare spots with more silicone and peat.
Allow to dry completely, and air out.
Slide the board back in the tank and add some silicone to the back to hold it in place.
right now there are just 2 green tree frogs and a chinese golden frog, at least thats what the pet store called it. I cant find it any place on the net. I am going to keep darts eventually, of course not with the other frogs. I just wanted to get these guys first to make sure I was going to stick with the hobby before I started sinking a lot of money in to darts. But I dont think I have to worry about losing intrest because I am HOOKED! I will post a pic of the golden maybe someone can tell me what he really is.
Yup, that is a golden gliding frog, R. leucomastyx. I had a bunch of tads of this species this year, but only a few made it to metamorphosis. They are pretty cool frogs. Try to get a pair, they breed pretty easily and make foam nests.