There are many tangs that you can put into your DT. A Convict tang would be fine, I feel you could do a sailfin or desjardini. I understand the hesitation with a Purple Tang, my 2" Purple Tang thinks he is 6". He is constantly trying to show dominance over my 4" Desjardini who looks at the Purple Tang like "settle down little guy". My Hippo Tang and Powder Blue Tang exit QT tomorrow so we will see how that introduction goes. Then my search becomes locked in on a 3.5" to 5" Blone Naso, then we try our luck with a 2" to 3" Clown Tang as the last member. If there is a remote chance of having success with a Clown Tang it will come with them as the last and smallest Tang in long aquarium. I'm a little shorter than ideal at 72", but I'm feeling good about it.