I'm sad to say that we lost both Dink and Prince (see photos in profile albums) in under 3 weeks, and now Whitey Bulger and Jerk are beginning to show the same symptoms that Dink and Prince showed before they passed.
Both Dink and Prince would start sitting on the bottom, only coming up for air before returning to the bottom, or floating in the corner. Both fish stopped eating, and both began getting tail-heavy towards the end. Both fish also developed a slight white fuzz to them, and on Prince, his tail began to dissolve, while Dink's head sort of began to deform a bit. We tried too late with Dink to start an antibiotic course, but we were able to get past the final day of antibiotic treatment with Prince, but he passed anyways. I'm not sure which antibiotics were used, other than that my girlfriend determined it appears as though the disease acts very similar to cotton-wool (columnaris), and so she bought antibiotics that treat for that disease. Further, her mom, a UCLA magna cum laude Master's graduate in ichthyology, believed it to be the same thing when described to her, but to no avail.
All of the chemistry for the water has been normal, and I've been doing regular water changes to keep the water pristine, with none of the water parameters changing from what they normally are. I started Whitey on a salt treatment yesterday, and gave him a slightly more-but-not-quite-double amount of StressCoat, in addition to starting him on the same antibiotics that we tried using for Dink and Prince.
I'm getting exceptionally worried now because not only is Whitey my first (and admittedly favorite now that Dink is gone), but he was bought several months before Dink, Jerk, and Prince, who were all bought on the same day, so I have a feeling it isn't just a bad batch of fry from whomever bred them, in the off chance they were all bred in the same location and same time. It seems like nothing I'm doing is helping, and I really don't want to lose 4 of my little buddies in under a month to the same disease.
Edit: Shortly before this all started happening, I started my fish on Hikari Betta Bio Gold, as the local pet stores no longer were selling the Omega One micro pellets. However, I haven't heard of anyone having issues such as this, and remember reading somewhere that the two were nearly identical, which is part of the reason I bought this brand in the first place.