I'm sorry to hear about your loss. A fish is just like any other pet and it is so heartbreaking to lose them. I hope you find out what happened so you'll at least have a "why."
Having any pet for that long and then losing them suddenly has got to be the ultimate heartbreak. I hope that the tank has recovered now and that things are back on track again for your amazing tank.
I'm sorry this had to happen to such a nice tank Deb, my regrets. You have always had a tank we could all be a little proud of. I'm sorry you lost your babies.