Man, I lost my first fish I had (or old enough to actually take care of) yesterday between 6 and 8 pm. I have no idea why he died- one day he was hanging out with me, he next he hurt his eye and started "playing dead" until he actually did die. He was the reason I started fish keeping and I can't believe he's gone. I actually got him as a white elephant gift and afterward I realized why I needed a betta.
Fortissimo (otherwise known as "Forte" and "Baby") died four days after I divided a tank and Azula (see above) jumped the divider and attacked him. He died overnight and so I came back from training and he was floating, a shock for me.
Both died within a month from each other.