I have been a betta owner since 1993. I have always raised them all the same way and they have lived for quite a long time for me. But lately I've had 5 bettas kick the bucket.
I bought a red crowntail, he was good for about a month then mysteriously stopped eating and within 24 hrs died.
I bought a blue crowntail, he lasted a few weeks and same exact thing happened.
I cleaned tank (5 gal. tank) very well and bought yet another betta, this time a regular red betta, he lived a week suddenly came ill and died 12 hrs later.
I cleaned the tank again, bought a different type of water conditioner, threw out the old food and bought a white betta. He seemed to do very well for a week then died as well.
I now have a blue crowntail, he is showing the exact same signs as all the other bettas. I expect him dead within 12 hrs.
In all cases, none of the bettas ever created bubble nests, all appeared to have swim bladder issues within 12 hrs of death. I noted the article about a new illness hitting bettas, it did mention gray coloring but the picture showed it on the tails. My bettas did get this coloring but it was on their faces, giving a "piebald" look even if the betta was not originally piebald color.
What really strikes me is that I know they tend to loose their color when they die but in these fish's case, they all turned very very gray very quickly after death.
An interesting side note about the current betta is how scared to death he is of everything. When I went to purchase him and touched the container he went NUTS darting around faster then I've ever seen a betta do before, since he was smaller I assumed he was just younger and full of energy. But when I brought him home he doesn't act at all like a normal betta, he swims along the tank decor and tries to shove himself into impossibly small hiding places, he will dart and hide for hours just from seeing me move from several feet away. I have had him for several days but in all that time I have only seen him for maybe a total of 5 min the entire time I've had him.
In any event I am about ready to throw in the betta towel.