My two bala sharks that I have had for nearly 8 years past away within one day on each other.... I assume it was do to old age - all the other fish are fine - and they were fine up to the day they died.... They had a long, good life. I have 4 silver dollars that are the same age. The dollars and balas have been together the entire 8 years. The dollars may be getting close to their life span as well.... 
