I agree, think its a male. You will definitely need to re-home the other female. A pair will most like Bully her to death. As to if they will pair. Who knows! You will be able to tell as bud said with rubbing. They will also stake out a spot in the tank and stay close to each other. Do small water change(20%) at least twice a week with the new water about 2 degrees cooler that tank temp. Feed small amount of frozen food like blood worn twice a day but only what they can eat in under a min. The combination of water changes and increased feeds will help spawning behavior and may help in pairing. If you don't see a pair form is a weeks time. It may not happen.