I have an adult Emperator in my SPS tank. I raised him from a juvenile and have grown very attached to him over the years. He is inteligent, beligerent, and he causes a lot of damage. He didnt nip at all for years but as he has matured he has become quite the little terror. He is a pet. He is in a 325 gallon loaded sps tank and every thing works since the tank is so big. My point is this. I would be broken hearted and this fish would be devastated if i moved him out of this tank. Right now, he rules the world. He is master of his domain. When he swims around he fears nothing. You can see it in his demeanor.
4 years ago, i moved him from my 180 into his new digs he was so stresed i couldnt hardlty stand it. When i started moving coral and he saw the rocks get moved he went and hid under a rock and just trembled. Before you put a potentially large angel into your tank please make sure you can keep the fish even if he becomes a nipper. The stress to you and the fish from moving and disposing of him because he has out grown your tank is substantial.
Understand that it is normal for adult angels eat coral. If you are going to get one dont you want it to act as close to normal in your tank as it can? If we are going to keep one shouldn't we make the commitment up front to accept that its normal for them to eat corals. Is it right to hope that they might not act normal when they grow up? Angelfish can live up to 20 years , they eat corals and they grow large. Rather than "hope" the fish wont eat corals, why dont we accept the resposibility that it will and if we are going to get one, then commit to providing the environment the animal needs for its entire life. Just because we like kittens doesnt mean we just take them to the pound when they turn into cats does it?