My chocolate molly, Cocoa passed away last night . I had gone away for the weekend and a family member had been feeding my fish. I came home today and she had passed away. I'm not sure what happened. She had been acting normal up until I left. No visible symptoms on her. My dad said she was normal and eating when he fed them. Water parameters are 0 ammonia, 0 nitrite, and 8 nitrate. I did a 50% water change before I left and all my other fish are healthy and active. The only thing I can think is that she had fry the night before I left. After that she seemed exausted for a bit but over all fine. I'm just not sure