i have two chromis and then about 3 weeks ago i added two more, and so far mine get along,,once in a while one of the bigger ones will chace the other one,but its no biggy...i hope this helps,,,have a great day...
I have added chromis to my tank several times with existing chromis in the tank. I have never ran into a problem. Matter of fact I had ones that have been in the tank pair up with the new guys like its the long lost freind. IMO. Good luck.