Have had mine for 3 years. Peaceful. Get one for every 2 linear feet in your tank. They don't bother anything but do like to have their territory. They do need hiding places. These are by far the best Damsels in terms of tolerating each other if you don't want a war zone.

I bought 4 Kupang Damsels and all have their own territory. The only fish that they seem aggressive towards are other blue fish. I do have a smaller Blue Tang and I have noticed some aggression towards it. My Blue Tang is only about 2", so it could be that it is fine with them when bigger. I will be finding a new home for the Kupang Damsel that claim the same territory as my Tang is more important to me. They do leave all my other fish alone though.

Bought two and they are very active and have stunning colors.