Red eyed tree frogs died pls help

[daybr4ke]

Hi! After reading through posts, I have a question: did you put your new frog, the one from Petsmart in a 30 day quarantine before adding them to the tank with the other frogs? This is a common practice to ensure thr new arrival is healthy and wont make your frog sick. Sometimes petsmart doesn't take good care of their frogs. The frog may have gotten the other frogs sick. Did the new one die first, followed by the other ones? Since they've already lasses, pictures arent a possibility, which makes the culprit harder to figure out, but we can still try to figure it out. Was there any redness on the underside of the frogs?
I'm really sorry for your loss.