Depends on their age. If they flash their undersides at you, as mine often do then you can see their 'lower regions'. If they appear to have two pink dots about the same size then they're most likelt female. Females tend to be rounder in the belly region, especially as the approach sexual maturity. A male has two pink bits too but the one further up his body will look slightly elongated towards the other pink bit. Lol I do word this so oddly.
Hugs,
P.
Yup, I spy the glowing eye. Mind you they both have that. Over the left, as you look at it.
Hugs,
P.
P.S:They don't sound or look like babies. Nice looking tank, although I can't see any other fish in there!!