Maroons are one of the hardest clowns to add a mate. A lot of aggression from the female and often fatal, may take a few trys. I posted this in the Clownfish board too.
Most any clown kept as the only one in a tank will morph to female quickly. When choosing a mate for it, pic from a group, not another individually kept one and not the biggest or dominate one from the group. If you can determine the dominate MALE then fine otherwise choose one thats small but appears to be active and brave.