Koi like to bully new comer ?

I just bought a Showa and introduced it to my existing collection of koi. Surprisingly, some of the koi keep chasing after this new comer. They are of the same size anyway. And i never see this kind of behaviour before among my koi. I don't think they are mating, because my koi are all still immature.

[spencertan]

Could be playful? I ever experienced that before,like they chasing but no injuries inflicted,so im fine with it,just that the koi may get more timid lor..