So guys, my platy was acting weird a few days prior to death. She would hide and not eat. She was also opening her mouth really wide and slowly and then she would close it...it just didn't seem normal to me...I need input
Unfortunately it's very difficult to tell with disease like this. By what you have described it could be an internal issue with respiration or sometype of a gi/intestinal issue. Although with that being said without pictures and physical characteristics its hard to determine
One thing that I've learned about this hobby over time is that not every disease is curable or treatable because many diseases are undiagnosable. A lot of times we can diagnose obvious common disease like ich, columnaris, fungi issues etc, but the reality is, is that many fish die from diseases that are simply hard to diagnose. There's a lot we don't know about immunology and pathology of freshwater organisms in a home setting. This could have easily been a bacteria, virus or internal parasite that your fishes immune system could not fight.