TheFishGuy
( Insert something funny )
I would like to have a couple of nice big koi in there, We will hope! ( but also it would be cool to have some mini koi )Several factors determine a fish growth (water quality, DNA, food etc), it may or may not be that the pond was too small, I've seen larger koi in smaller than 160gl aquariums.
Years ago we bought 5 koi all from the same batch, 4 of them grew over 2', and one of them is still the size of a large shubunkin
I think your fish are still young and with proper care could surprise you...unless of course it's due to DNA