My betta, Spike, died last night. He'd been lethargic for a couple days and had some fin rot. We started treating with antibiotics, checked and changed the water (pH was high, so we added reducer), but it was apparently not enough. The test kit showed ammonia as slightly high but still okay, but this was right after a water change, so there was probably too much ammonia.
This was my first betta, and my first pet fish, so I was, and still am, pretty upset. I'd had him for just about a year.
This is actually why I joined the forum, because I'm hoping to find a breeder near me to get a healthy fish (Spike came from Petco), and also to learn more about keeping bettas happy and healthy.