I too cycled my tank with damsels. I placed 2 blue and 2 3-stripe damsels in. The 3-stripe would team together and the blue would do the same....which was kinda odd in my opinion but things happen. The 2 "armies" would always try to charge one another and a couple of them started showing signs of fin loss. I recently purchased a rather large cleaner shrimp and although it makes me laugh every time I see it, he plays referee. He actually positions himself right between the 2 groups of damsels. I am not sure if this is normal but the damsels are scared to death of the shrimp. Any time one of the damsels tries to go towards the oposite side, the shrimp immediately charges in and fends them off. Oddest thing I have ever seen. I have a peak of live rock that I reach down with food and the shrimp hops up to eat from my hand....wjile doing this, if he sees ANY attempt by a damsel to attack the other..he rushes back into position and resumes his "honorary mediator" role, hehe.