I added a new angel fish to my community tank about 2 weeks ago. I previously had 2 angelfish which got along good, but now one of my old angelfish formed a couple with the new one and all hell is breaking loose with the 3rd one. They don`t accept it in their gang and they are constantly fighting, as time goes by the fighting is getting worse and worse. I``ve moved things around in my tank, added new plants, nothing seems to work, so now I am asking you guys for help. Thanx
RIXX

Rixx, the problem is that the one that you just added may be a female, and the others that you had previously are male this is going to cause an issue between the males, they will fight and pick at each other until one of them is dead, unfortunately there isn't anything that can be done at this point other than to remove one of the fish, if you have a "pair" i would not want to remove one of those i would take out the fish that is getting beat up and maybe put him into another tank or take him to the pet store as most will work out a deal with you for credit.

hope this helps even though it's not the answer you are looking for.
Brandon