When I went to bed last night she was fine! Active, healthy appetite! Turned the lights on this morning and she's sitting on the floor of the aquarium, has turned splotchy white. Big change since she is normally VERY dark! Barely any gill movement at all, then she's thrash a bit and then be still. Now...she's just dead!! Waht just happened!?! All my other fish are fine. Tested the water it's perfect, 0 ppm on Nitrites, Notrates and Ammonia. The pH is 8.0. This is the first time anything has happened like this....please tell me what just happened to my favorite fish!!!