Luckily the rasboras haven't been in the same tank as the cories yet, so their fine. Although before i moved the cories to the 40 gallon, one did get a very nasty case of columnaris that i couldn't treat in time and he didn't make it sadly. None of the others got it however and that was over a month ago.
I went back to the pet store the other day and some of the rasboras there had the same mouth fungus that mine had, so i know it came from there. The neons however, i still think the sand poisoned them since they were in quarantine for over a month and did great in there with no issues or deaths until the move. They were both from the same place though.
I don't really know what to do with the rasbora's now, they get their second dose of sulfaplex tomorrow. Most are doing seemingly well except for another one which is hanging back now, i'm expecting to find him dead tomorrow based on the current track record...
I changed the water a little bit more frequently because i wanted the fungus out of the water, like every other day or so of about 40%. But now it's back to once a week. I'm hoping the water changes aren't the cause of the deaths, i suspect it might be a change in ph now from the water changes that's hurting them (i have almond leaves in there that soften the water and supposedly help to keep them healthier). Though i tested it and the parameters are about the same between tap and tank, just the tank water is a little softer from the leaves.