Here is my kuchibeni kohaku after 4 months of keeping.
He (I suppose from how yelloow the head is) starts at 25cm in december 2018 and measures 43cm early this April 2019.
Earlier on his growth is exceptional, reaching 9cm over the course of first month.
I eased his Hi silk growth food a bit and changing the diet partially into hikari wheat germ dan JPD akafuji color enhancing food.
Sure enough he grew more slowly for the remaining 3 months and gained most of the beni quality back.
Wishing for a good progress on body comformity, skin and size in the next few years.