Keep him in the QT; you did the right thing starting him there. Contrary to what a lot of folks seem to think, a fish isn't "happier'' in a DT. CBs are tough fish to acclimate and the competition and harassment (CBs like quiet surroundings) in the DT would just make acclimation tougher. Also, there could easily be something wrong with this fish that could spread to all your fish. We always watch for parasites in a QT, but I'm sure fish can have all sorts of unknown (and contagious) problems; just like people and other animals. MY CB didn't eat for 7 days, and I really don't think you're at the crisis point yet (getting there). I agree with the above posters; if he won't eat blackworms, live brine, or fresh clam---he isn't ready to eat anything. IMO, moving him will just make his problem worse. Unfortunately, a lot of CBs never do adjust to captivity.