Now that Rex has passed, Azazel will have the tank all to herself. I have no idea what killed Rex, but he was quarantined when he died. Azazel was still in the tank, but I quarantined her just to be sure she doesn't fall ill to whatever got Rex.
If this happened with your fish, what would you do with the tank? Would you just clean it with hot water? Would you bleach everything? Would you change the filter cartridge?
I would really appreciate your opinions no matter if they contradict each other or not. I just need to know how to go about doing this.