ZZ RD. Its hard to tell at 3" but my guess is its a male. To get a bigger KOK and color really depends on genetics, but you can help it along with good clean foods (ex: NLS pellets, market shrimp, Hikari krill, Hikari mysis shrimp, Hikari bloodworms, Hikari spirulina enriched brine shrimp, etc...), clean water, and I like the mirror trick to make him feel dominant. Dominant males tend to show larger nuchal humps. Good luck.