Betta - Swim Bladder? Bloat... Maybe Dieing?

[PrairieSunflower]

I don't think his death was a diet issue anyway.  He did become fussy and stop eating things other than the pellets, but he was eating the right number of pellets and not seeming to ever have any constipation issues.

I am considering not getting a replacement betta this time though, they just don't seem to be living for the length of time I expect them to, and all three have died of different things (the first had to have been sick when I got him, the second a bacterial issue, and this one a mystery).