I have been keeping corydoras for a while but have never really focused on them, I got 3 bronze corries before for my discus tank and I was reading some info on sexing, and two are super fat which I assumed they just loved food too much and their heads are arched up slightly, but when I thought about it the other one has grown but only half the size of the other fat buggers and its head is aiming up, so it suddenly dawned on me that maybe one is a male and the other two are females, I also went and got two julii corries today, they are in a heavily planted discus tank by the way.