about a month ago i noticed mt NTT had a sort of white fungus on the dorsal and along the one side of the body. i removed and placed into quarantine and treated with API PIMAFIX for the better part of the month until there was barley a trace of fungus. it wasn't really eating in the quarantine tank so i placed it back into the original tank. after a couple days was eating krill but i noticed the fungus coming back so i once again placed into quarantine and have been medicating as per direct for all of this week, i woke up today and it was dead. not sure why and didnt see it coming. now im noticing another NTT from the same tank has the same problem. what should i do to prevent this one from dying as well? all water parameters are normal in both tanks.