I do what I can to control them. If I have problems I will not ship. I also treat with copper lightly. I recommend a 3 to 5 min. Regardless of who you get your fish from you should follow these rules That way you will not get any parasites.
Strong colors are dominate.
Most damsels are aggressive. Other then that most fish get along, with a few exceptions. Tom's Caribbean Tropicals Inc. Tavernier Fl.