so all today my dat was looking fine and healthy. I went to an aquarium store and was gone maybe an hr or two and came home to look at my dat lying on the bottom of the tank...he is stiff but still breathing so i netted him and his sitting in the net not able to move. he is still breathing but floats upside down without support. ive seen this happen before with another fish and i know he will die but does anyone know why this would happen? my ph is 7.5 and temp is 82, i read they can handle ph between 7.6-8.0 and temps from 80-86, is this correct?