clown fish questions.

hey, im new to the forums and new to the salt water scene.
i have a question on some clownfish i just have.
i have two oscellaris and one percula and the one oscellaris was in the tank a couple days before the other two were introduced.
the purcula is digging a hole in the sand by the live rock, kinda under the rock, and staying down there while the other are out swimming together and doing whatever. occasionally the ocellaris clown fish will swim over, the new one does not have a problem with the percula, its the one that has been in the tank for a couple days that does this weird dance or shiver and swims off.

please let me know whats going on, and what i should do. i would love to keep the percula if possible.
thanks!

 

that dance is submitting to their dominance.

clownfish pair up in a family, with one becoming the female, one becoming the male, and all others becoming the "kick around fish"/unsexed that live to take the place of the male should he die or take the place of the female. In the wild there are several of those unsexed fish the aggression is spread between them but with only one in the tank I think he will have a sad life of being picked on.

 

should i buy one more true percula for him to be with?
thank you for your help.