A death in the family

A completely different fantail goldfish that the one that kept floating upside down died today. I didn't even know it was sick. It was the largest and prettiest. It was about 8" long including the tail. I had it since it was about 2 inches. One of the tetra's has ich I think too. The goldfish didn't. Not sure what is up. I guess I need to do a full tank cleaning and disinfecting. Melafix is great for getting them healthy again. These fish are old though so they might just be ready to give up the ghost.