First consider the advantage of a lightly stocked aquarium, sooner or later there will be equipment failure and the more heavily stocked a system is the quicker things will can go wrong. There's also grwo out to consider, as generally if a fish doubles in length as it grows it's body mass may increase by a factor of 4 or 6 so you effective bioload has increased by 4 or 6 times. So after figuring your systems biomass in a year or to after everything has grown and you still think you have room for more biomass I'd suggest more Bangii Cardinals, they will do better with a small group of 3-5. You could also get another clown and/or a pair or trio of Orchid Dottybacks or Royal Grammas or Assessors, keep in mind you can't mix them!
