well, if the last one doesn't die and you plan to get more, I would qt any new frogs for at least a month to make sure they are free from illness before adding them to your established tank. If the current frog dies, I would wait at least a month until you get a new one. It seems to be hit or miss with adf's lately. I would recommend going to the store where you plan to purchase them and observing the tank for a couple of weeks before you buy more. If you see any that are having symptoms similar to what you have observed, don't buy from that store. If you buy from the same store (and this is assuming your frogs had chytrid) and they restocked without waiting/sanitizing the tank, any new frogs they put into their display tank will be exposed and theoretically could get sick or transfer the illness. I would probably get them from another store after an observation period and then still qt.