Most of the diamond-shaped(or deep bodied) tetras (Phantom Tetras, Bleeding Heart Tetras, Serpae Tetras, Candy Cane Tetras, etc.) seem to be aggresive to each other and nippy. I'd recommend increasing the schools if your still gonna keep them.
Great fish, but rather a lot of "character". Big schools are the solution. Males can be pretty vicious to each other. They're not unlike tiger barbs in behaviour.
Well after doin my A.M check before work It seems that the aggression against my other fish is gone. The last 3 school around the bottoms. Theres some light chasing and flashing but I can accept that. It is the nature of the fish. I guess the one i seperated was the trouble maker after all. He used go lead the attacks on the other fish. I feel like if I wouldve added more the "pack" wouldve just gotten stronger.