I have had an incident of mass deaths among my Bettas. Please refer to this: http://www.bettafish.com/showthread.php?t=102768
to see how it started and what happened, in-depth.
In short, three of my Bettas all died off one-by-one, starting with color loss and erratic swimming/swimming on their sides, OVER NIGHT. It is unclear if this was because of TB or because of a bacterial infection, but it caught them all because I used the same cleaning supplies on all of their tanks (a lesson now very much learned). Their fins started falling apart and they became very lethargic before passing. I can't even begin to explain how much my heart is hurting right now.
#4, Calvin, the very last Betta to contract the illness, was doing just fine a week ago. There is a video of him in my blog, second to last one on the 2nd page, of him swimming around happily a week ago. The very next day, he was in the corner of his tank, sitting on his head, all day. If you do go through my blog (you don't have to to track this process), you'll see videos of my Bettas the very days before they died, perfectly happy and healthy.
Calvin was put on Tetra Lifeguard All-in-one-treatment for a five day (5 day max) period after the others died, and he was doing fine. It ended yesterday, and now he's doing very poorly again, not moving, and what was once beautiful turquoise is now completely grey, but for bits of red streaks here and there.
Calvin lives in a 2.5gal tank, heated, proper water/ammonia levels, filtered tank with biweekly water changes and Betta Bio Gold 4 pellet daily dinners.
Now I'm afraid Calvin, too, is going to end up dead in the morning! I don't know how much more of this I can take. Can someone please tell me what happened to my fish and how to stop it?
FYI: I have one Betta, Versace, who was never exposed to the same contaminants as the rest. He is perfectly fine.