| The answer is yes, tosai can catch up. This statment changes however every year they get older until the 'damage' is more or less permenant. Koi are inderterminate growers but the % of grow slows with age.
As you say, breeders crowd them all in winter and they all catch up in summer.
And as Momotaro said, in that famous experiment of his- the siblings of 'pushed koi' were notably smaller after one year. But during the summer, the wintered tosai caught up to their larger babied siblings.
Just remember that at the end of the day, a koi can not grow faster than, or GREATER than, it's genetic limitations. So knowing that, a koi can only really be held back by environmental factors as long as they exist. - JR |