If a flowerhorn can see another flowerhorn in a divided tank it will effect the kok growth in a big way. I experienced this personally with about 4 juveniles that I raised. When those 4 juveniles got into a tank by them selves without the presence of another fish their kok became huge! Flowerhorns are fine not eating for a week as long as they are healthy going into that fasting period, just don't expect any growth. Also I feel like I need to clarify my "good markings" comment since you are now using that term. When I said "good markings' I should have said "flower line" or "plums" describing the solid black line running down that fish's side. For many hobbyists this is a desirable trait.
If you're saying if flowerhorns are in tank theirselves grow kok bigger is wrong. You might be right about size growing faster but not kok.
Explain to me why most hobbyists or farmers put their flowerhorns as small as 2 inches or bigger in a tank with others in a divider and later still in divider with extremely big kok?
They know how to do it, that why people are buying their flowerhorn. Even websites say it make them more aggressive, putting two flowerhorn together with a divider that they can see each other increase the aggressive level which play A big role in kok growth
