If they paired they will fight! if they not paired,usually the bigger one win the anemone! remeber, tank raised percula might not take anomone at all, my 3 percula, i tried carpet,bubble, long tentacle. now they end up with goniopora!
remeber, now they are small, when they gettin bigger the chance they fight will increase! if you add percula or tomato, the famale will be very aggressive to other kind of clowns.