Dont listen to snap about the fish heads and feeding live. Feed it on shrimp, tilapia, mussels, and a variety of other white fish. Also try to get it on pellets as soon as possible. Getting him to accept a variety early will make it cheaper whens he is bigger and healthier then feeding live.
Also everything frontos said above me is great info. Although I keep my juvy rhom in a 29 for the time being, if you have the large tank to dedicate to your black thats great.
As far as setup I suggest some driftwood and live plants if you have a green thumb. One of the best tanks I have seen in person was someone from piranha-furys. He had a 7-8 inch rhom in a full planted tank. The fish looked amazing in it.
Like frontos said, put the driftwood and bigger plants on one side and allow a powerhead with a lot of swimming room on the other side with foreground and cover plants on that side.