I put these in not even a week ago. The LFS I went to wasn't positive about sexing, but currently, the two are following each other everywhere. The first couple of days, it looked like they may have been fighting - the one I assumed to be female (flat tail fin) would charge head first at the side of the male's body. On a couple occasions, one would quickly dart at the other to chase it off and they did also do some minor kissing that didn't last too long. I haven't seen that at all in the last few days. They act like they've gotten used to each other. https://www.youtube.com/watch?v=aPRqTpvz23E What do you think?