About a 1 month (month and a half) was when my Indo Tusk took a turn for the worst. He was strong and healthy, but after 3 days total in my display after QT (4 weeks), broke out with lympho. Removed him back to QT, where he later stopped eating (did eat for couples days after being re-introduced to QT) and slowly became worse and worse with heavy fin rot and nasty infections. I eventually decided that the infections are painful and all he was doing was breathing. He was past of the point of doing the "death spirals" doomed fish do, yet he lived on for another 2 days lying lifeless on the tank bottom, till I put him down.
I had 2 previous experiences with good Indo Tusks living for many months before being lost to stupidity (one jumped, one lost to Ich/Velvet outbreak). So not every Indo Tusk is doomed. However the experience has left me jaded, and I will never again purchase and Indo Tusk nor recommend buying an Indo. The bottom line is there are reasons Austrailians are over $150, yet if you know where to look, you can find Indo's for $39.99.
My theorm on what happened to mine, is Cyanide collection damaged a major internal organ or imoprtant internal system, that eventually failed.