I regret to advise that most of the koi should have been culled when small, and somebody sold you koi that should not have entered the market?
The Kohaku is not bad and I would keep it, but the others will all go from bad to worse as time goes on and has no potential.
In my opinion it is not worth it to grow on low quality koi in viw of the costs running a koi pond. You can get much better for a couple of bucks or even collect better quality koi from me free of charge if you are in the Cape Town area.
On the other hand, if they give you pleasure and you like them, who are we to judge.
Whereabout are you?
E Mail: email@example.com ; http://www.koionline.co.za
Koi are not my whole life but make my life whole