hippo tangs can be a little tricky sometimes...but I found that buying a healthy fish is very important to start with. I would purchase medium sized hippo tangs instead of juveniles and I would ask the local fish stores to feed them in front of me to make sure that it does indeed eat. But even before that I would make sure the tank is large enough to house a hippo tang to begin with and there are no other fish that might scare it off. Once you get the ich then the real only way to treat it is put it in a quarantine tank...