So CrystalGemini and I went into the same Petco we purchased
Ash from, to talk to the one sales associate whom helped us pick up Ash to assist us in getting him toys and stuff (we bought him a hammock and a ball!). I had given thought of maybe getting Ash a companion chin in the future, and asked if any of his brothers were still available and the sales associate interrupted me before I finished.
"Oh my God, I have been waiting for you guys to show up. It's about his brothers. We had to put them all down, except for one, because they got ringworm. We're treating the last surviving one right now."
We asked about the syptoms and loss of hair is the biggest one - Ash had lost a large amount of hair shortly after he arrived. But I chalked it up to his defense mechanism kicking in when he was unsure of me trying to grab him to put him back in the cage.
The surefire test is to hold a black light to them and the infection shows up as a green, scabby-like infection on the ears. He showed CrystalGemini and I the chin that they were treating, for almost two weeks (right when we got Ash), and even after all the treatment, it was green all over. Gross and sad.
We went home and tested Ash underneath the black light and he was clean. Plus, he loves running around in his ball. What a lucky fuckin' chinchilla. Had I not got him and he stayed in the pen with the others for just a day or two longer, he would probably have been put down.