Sorry for your loss.
I know you want to keep it as natural as possible for your fish. What I have learned over the years is there is nothing natural about how these fish are collected and shipped half way around the world with many stops in between getting to our tanks. The good news is you've got your QT tank now and have read up on the medication procedures if needed.
As far as trusted sources to buy fish from. Personally I now assume they have some kind of disease when I get them. Observe in QT and treat if needed.
Good luck with tank. It sucks I know, but it happens to everyone that has been in this hobby for any long time.
I know you want to keep it as natural as possible for your fish. What I have learned over the years is there is nothing natural about how these fish are collected and shipped half way around the world with many stops in between getting to our tanks. The good news is you've got your QT tank now and have read up on the medication procedures if needed.
As far as trusted sources to buy fish from. Personally I now assume they have some kind of disease when I get them. Observe in QT and treat if needed.
Good luck with tank. It sucks I know, but it happens to everyone that has been in this hobby for any long time.