Hi everyone!
I have a community tank that started with one female betta, 5 false Julii cory catfish, and a school of cardinal tetras. A few months ago a bacterial infection ravaged the tank, and despite medication and my best efforts, all but the betta, and two each of the tetra and catfish passed away. I know the tetra and catfish can't live happily without a larger school, but I'm concerned that introducing new fish, even after quarantine, might leave either the new fish or the current fish prone to diseases the others carry, especially with cardinal tetras being wild-caught. Should I opt for the captive-bred neon tetras, and will cardinals school with them? And how can I safely and ethically introduce new fish?