Now today my all black angels tail is splitting i dont kno what im doing wrong plz help i dont want the to die
This alone and of itself is very unlikely to kill the fish. I have as I mentioned seen this with characins, and the fish live for years. Black Phantom used to get this, and Rosy tetra, others too.
However, all possibilities for the cause should be investigated in case there is something causing this that could worsen. We have mentioned aggression, which is the most likely. Sit in front of the tank very quietly for an hour. Once you are quiet, the fish will forget your presence and behave more "normally." Watch closely for any chasing, nudging, nipping, swords sneaking up behind the angel, etc. I'm quite serious about being absolutely still; any movement will cause the fish to think about what is going on outside, and feeding will pop into their heads, or predators, and they will not behave "normal."
Second though is water quality. Have you tested for ammonia, nitrite, nitrate, and if so, what are the numbers? What is the pH? And the GH? And the temperature?
Byron.