your lil cutie screames "im a boy" in just about every way til i look at the belly and ventrals which says "im a girl" so im not much help this time but this lil one is very cute no matter what. only thing i can recoment is try to get a look or even a picture of its belly and look for the oviposter (egg spot) between its ventrals. that should help to determin the sex of this fish, but keep in mind that males can have this also (my latest addition does and he even looks a bit girly in comparison to his sister)