Very nice, Ive kept Daintys in the past, they are my fav frog.
To answer your question, I had 2 that both stayed yellow while in my care (about 2 years).
Then I past them on to a mate that had a colony of them.
Last I saw them, there was 9 in his colony (4x yellow and 5x green)
Great looking setup as well, Im liking the bramiliad.
Just make sure its planted in chemical free soil (coco pete) topped with gravel.