I've read very recently about it, the was a study done about UVB and frogs, temps were mentioned too, can't recall details now, I was looking more for UVB effect in captivity. anyhow i do remember these frogs change color depending on a mood and tank temps, the color gets dull when it is stressed out and a frog turns very dark brown if a tank is too cold, that would be your case i'm assuming. UVB is a must, real unfiltered UVB and suspended above tank basking lamp. i remember reading and thinking that these would very cool to keep, big and aggressive, pacman and pixie mix that is active during a day lol