I would love to chime in, Yes FH koks can change as they age. I have a Red Based Male King Kamfa and his kok continues to gain pearling and coloring as he has been aging. I got my guy at 3.5 inches and now at 6 inches he almost looks like a totally different fish, but in a good way. His kok is now pearling all the way across and his kok is getting red patches. Each passing week I am amazed by his coloring and development. I agree with what many that have said about staying away from hormone enhanced food. Like you said, I don't believe NLS makes a hormone enhanced food but either way its good to know that feeding a high quality FH a well balanced diet and keeping their water conditions ideal will give you the best results. Master Breeders from Thailand and here in the USA will tell you that its very healthy to incorporate vegetable into their diets. I feed mine Hikari Excel for my FH to get his dose of green plants. I also feed Hikari Bio Gold Plus, Gold, and Hikari Blood Worm, and my guy is growing like a beast!!