Swim Bladder Disease?

#1
I have a female molly that is swimming very oddly lately. From what I have read about swim bladder disease... it causes them to swim in weird fashions. My molly seems like her tail is too light and her face is always facing the gravel. It is as if she cannot move her tail to swim or like her rear-end is much lighter than her head and it causes teh tail to float, so to speak. What could this be and what can I do to cure it? Thanx.