i have no idea either. but if you find out let me know so i know what i have..lol

how they act. way i tell get three in a tank and if two start fighting that means their males usually unless u got all 3 males lol

Male red zebras typically develop a blue tinted dorsal fin. Their bodies also become more pinkish (with a blue sheen) as they mature. Fighting is definately not a gender indicator. My most aggressive fish is currently a female msobo; and just last week I had to relocate a female BB zebra because she was trying to demolish the other female. That's a plump fish there! Might want to reduce feeding a bit or bloat might develop.