Obviously it wasn't taken care of because a week of this guy having it and it is magically better.
Who knows, maybe it was rook's optimism that allowed the ray to gain weight...Wait no, that doesn't make any sense, it was porbably the food it consumed that allowed it to gain weight.
Great job rook, ray saver.
Just for the record what have you been feeding it? And how much is it eating?
Congrats Rook! She is getting much better! Doing a great job but like everyone is saying I would try to get her in a bigger tank soon and do a very long slow acclimation not to stress her