Bomb, I'm so sorry, too. AND sorry for the gross-out factor. When you can just get their body out & put it in the garden quickly, it makes it easier. I lost my white girl, Flake, last week. The white ones' seem to catch all the colors...sooo pretty :0(
I've had a fish disappear, except not a betta: 1 cory and 1 LARGE Amno shrimp. The shrimp were in a .5 gal QT tank alone- if the others ate it, it certainly must have been within :30!
An interesting note: my name is Melissa. In high school, my best friend was named Andra. She died of a sudden illness in the October of our Senior year. I was considering naming my 1st baby (human baby) "Andra" but he was a boy. I never got around to having a girl.