Hi - I have 4 that I have owned from about 1.5inches (3 years ago). It turns out I ended up with 2 males and 2 females. The one male colored up at around 7.5-8 inches, while the other did not show any signs of color or being a male until around 9+ inches. They are in a tank with other haps, whom at the time were bigger than them so they were by no means the dominant fish in the tank from the start. In my experience they were very slow to color but once they started to they really pop and it is very rewarding.
Slight yellow tone, however the male that showed no color until 9+ inches looked identical to a female. I vented it and posted pictures on this website amongst others and every one said 100% certain it was a female. Once it got a bit over 9inches it quickly turned colorfully, what seemed to be overnight change.
I find them to be very entertaining fish and rewarding but require patience. Now the Pairs breed regularly with the females holding north of 60 fry at a time.
I had a male a few years back. I bought him from a fellow hobbyist. He was around 10". I remember he was very aggressive with all my haps. I also did have large haps in my 220. I had him for a few years but then he must have died of old age because he started losing his color, lost a lot of weight, and just didn't move around much. He finally past. Pretty fish though.