How long should your tank be up and going before buying a purple tang I've read that they are very hardy but doue to there expense I don't want to rush buying one to early said:
Just an opinion but... If you want a purple tang let your tank cycle at least another 4 to 6 weeks IMO. Any and all tangs can be territorial and parasite prone, so selecting based on those criteria will likely get you confused and tangless. Providing a stable environment for optimum immune system maturity is the key to keeping tangs in my experience. Purples are extremely hardy but any tang needs a stable environment with plenty of dirty rock to graze on to be happy. What size is the tank how often are your water changes and how many gallons do you change just to have a decent idea of bacterial maturity.