I'm really sorry to hear that he died, but it is an unfortunate part of this hobby. I have had a couple die and it always makes me feel awful. They are "just fish," but they are still living creatures with their own personalities that rely on me to survive.
That being said, my Tusk was an 6" adult that cost me $180. Even at that, he was still bullied by my yellow tang who was 1/2 his size. Some people say to attach mirrors to the side of the tank and the tang will become obsessed with the "other tang" in the tank.
My tusk spent the first week hanging out vertical in the corner of the tank. He eventually go used to his tank mates, but the tang would always occasionaly go over to tail slap him when he was sleeping.
Saltwater Aquarium Fish for Marine Aquariums: Harlequin Tusk