Why would my frog go from being bright green when I got her, to being permanently brown for over a year, when my OTHER American Green Tree Frog stays bright green? She eats regularly and acts normal. Everything in the tank is perfect (humidity, temp, lighting, plants, substrate, water, etc) The only thing I don't have in the tank is a background, but I didn't put one in because my frogs prefer the light coming through the window behind their tank than the plants and branches that I have in there. Plus, it's a spinning tank, I mean it turns in circles, so you can view it from all angles. I've heard its normal for them to turn brown... but is it normal for them to stay brown all the time??


Here's some pics from when I first got the frog and she's in the quarantine tank, and from now in her current home.
Then:



Now: