Is it showing anything kok wise? At 6" it'll probably only develop a hard kok. If it's not showing ANY kind of water kok , then there's probably no hope for one.
Feed it a high fat, low fiber food.
What size tank is it in? Do you have room to toss a ParrotFish, or 2, in with him? Give him something to push around& assert dominance on. It'll help
I agree about the Quality of FH with the local breeders. You basically HAVE to spend your money overseas