The nova will keep most corals but a tek will take care of anything you want to add. On the fish list; please do not add any kind of tang. The smallest tang needs a min tank size of 55 gal but I think a 75 would be better. Tangs are known for getting ich and in a 40 gal they will get stressed and have a even better chance of getting it. Tangs are fast swimmers and need alot of room. I don't know much about the hawkfish, so look into it as I thought they were not reef safe, but I could be wrong. A dwarf angle would be good and there are some beuatiful ones out there.