In any group, one fish will already be dominant.
If you wanna avoid the chance of fighting and your LFS has 1 tank with clowns, you can pick the dominant 1 & any other fish from the hirachy. If there is separate groups to pick from, again go for 1 that is already dominant in 1 group and then any other sub-dominant fish could be paired without much risk of trouble.
I asked my LFS to order a specific variant and he was kind enough to order four so I could pick two I liked. Their size was definitely "similar" but two was slightly bigger and he had to separate one. I picked the "bigger" one he alone and the best looking of the two smaller. When I acclimatise them, they already showed different attitudes and when they were released in the tank, the big one ignored everything but her reflection.
The smaller one quickly learned to watch her back for her and started luring her to the other corner of the tank (where she emediately confronted her reflection). Here the small one looked around while letting her know he still "had her back" and discovered the LTA in a cave right near by. It had retracted while I was floating bags and turned off the powerhead.
Now the sub-dominant had to get the attention of the bigger one, so he could get closer to the anemone. She quickly saw it and they began marking out their turf.
First they both marked a corner of the anemone's cave and during the next days they made sure the tank was safe from possible monsters and clearly expanded their turf. At
Ahis stage they were completely used to a partnership of protecting eachother and the submissive fish constantly showed the bigger it was boss. They figured out that the reflections did nothing to their turf and now pretty much ignore them.
The boss still wanted everything (especially the anemone) as her own turf. By now she has basically the smaller one submit in every possible corner of the tank. In the first days she ran him down until he tired and he seemed to then semi-hypnotise her with all that clown stuff. Sometimes he just maked a tactical distraction by swimming towards the anemone and she will go to guard it and he can escape, or sometimes he will risk it and dance with her in the anemone until she'll chase him again. Now they patrol together every morning (rest more during the midday) and after patrolling the tank at evening, they systematically do clown dance in every conceivable part of their tank (they are the only ones there except the anemone).
Anything to make the hirachy turn the right way, and you'll be safe. If they don't know who is to be boss, they will have to fight.
In nature, one would leave, so this is hard for all parties when it takes place in our tanks.
They must not lock jaws, if this happens and does not pass and is replaced with a clear developing colaborative relationship, but continue as jaw-confronting battles, they both wish to be dominant and I have read people state that then you will have to separate them and find a new mate.
Sorry for the long answer, I still have 15min more before I usually go look to them in the morning time
I don't know if you know this but they make many sounds these fishes. Some weeks ago, the apartment upstairs had a party that was pretty noisy. That morning I actually came in to find the smaller fish with it's head actually stuck inside a rock crevice. It's body was sticking towards the open sand where it usually sleeps, very awkward looking position but I guess it worked since it slept there all night..
