Phew. My juvenile female bullfrog, Gnag [Guh-nagg] just changed from brown to green. I was really worried about her, but then I read this post.... I do know that they turn dark green, not brown, if the water is bad, and the water is crystal clear, so it must be the fact that she hides under a log for most of the day. Thanks, guys I was really worried about her. I'm new to the forum, so advice on keeping bullfrogs is GREATLY appreciated.