Well unfortunately a 75 is too small for all tangs except those that grow to a maximum of 6"-7". There are a few members of the Ctenochaetus genus that fit the bill, but that is about it. These aren't the most colorful of Tangs, nor are they the easiest of fish (they are known to be picky eaters, and can be aggressive as they mature). If this is a FOWLR, I would recommend a Coral Beauty Angel, which is one of the easiest of the Dwarf Angels, and also one of the least likely to pick at corals. Other options would be Firefish (only one per species though), Royal Gramma or another Basslet, smaller Hawkfish such as the Flame, Possum or Flasher Wrasse(s), smaller Fairy Wrasses, Midas Blenny, etc.
Keep in mind almost all of the fish I mentioned need a tank that is 100% covered, either by 1/4" clear mesh (preferred) or glass tops.
