I have had many tangs congruently, including a purple and a yellow to date. Fish, tangs in particular are aggressive for two major reasons: Territory and food! They have to have space and have equal opportunity of food. Feed, Feed, Feed! When you get them first together, then once the behavior of peace is achieved, you may cut down feeding to-need (BIO-LOAD). Other side of the coin or as Paul Harvey said; "Now, the rest of the story." Fish have personalities or seeing how they are not people, fishonalities. Some as most, will either get along or tolerate their tank-mate(s) and other inhabitants and lead a peaceful tankhood life. Others, are like certain people within a society. They will bully, chase and nip other fish until they are ran into exhaustion until death. It comes down to this when it concern us as aquarist: It is a spin of the wheel as to what fishonality our fish will have when we purchase it. If the fish is truely a bully, it is best to get him/her to an environment that it might integrate better. I cannot emphasize enough the importance of Research and planning, they are the key to this hobby and if the Reverend doesn't mind me saying so. When I was in the NAVY we had rule that what was called the 6-P Rule: Prior Planning Prevents Pee Poor Performance. I still use it to this day as much as I can...especially in this hobby! Good luck my fellow aquarist!
Ernie
