I did a 100% water change after he died, and he didn't die within the tank, I put him in a cup in the tank so he would be heated. Here are some general stats for you anyway:
Water Changes: 100% once every week, sometimes a 50% and a 100% per week.
Around a 10 Gallon Tank in size.
Both the male and female had the same symptoms, breathing heavily at the top of the water, then would float back down a little bit. Ace would lie still though and i'd have to triple check to make sure that he wasn't dead earlier on. Those were the only symptoms.
Mulan: Blue/Green/Red HM Male
Those who now swim in the Rainbow Ponds:
Spike: VT Purple Male
Glaedr: CT Yellow Male
Ezio: DeT Dragonscale Male
Stu (Founder of the obsession): CT Blue Male