i dont think rtcs have external differences when it comes to gender
what plans you got for him? seeing as you didnt know about gender differences im assuming you dont really know much?
Not to sure, but i though i read some posts from you asking abunch of queston on rtc AFTER you had got 2 of them and put them in like a 20 gal?? Does that mean you dont know much about keeping fish???
my RTC was that big 1.5 month ago now he is about 9-10inch i think i like them when there small cuz there so small lol