Fish can be territorial. Adding new fish can always instigate aggression and wars. Do you risk breaking the balance for pretty additions, or keep things still?
I have had a tank bred Flavescens for months and added a Xanthurum recenty. The Flav is aggressive and stands its gound which explains why its tail and ventral fins are ragged and split with the Xan being 30% larger and from the wild. After a month, its still going on but the fights are becoming more civil and the Flavescens is starting to heal up. It should be OK but its taking time. 220 gallon tank, 11 fish. The fish I want are no longer available regularly. Stocking to plan is going to take time.
I try to make an effort to "reset" the rock work a bit each time I add new tangs to shuffle up their existing territory. Doesn't always work but helped with a few situation.
