They look great. Very healthy. As many others have already stated, once they get around the two inch mark, it should be much easier to sex them accurately. As also mentioned previously, the females will have much more blue on the operculum.
DwarfCichlid101 is right. But unfortunately that is not a very efficient rule. Sometimes ... some females are very dull in colour.... all the way ... even gills. The females are usually the smaller fish. The dominated males may also have very dull colors but the females might be darker. I would say that in 65% of the cases ... the females have a iridescent blue gill plate .... the same colour the dominant male has all over his body. And usually males aren't very passionate about each other .... they are quite aggressive from small sizes. My male JD killed 3 4" bros when he was just 4.5".
its been 3 months now since i got the JD´s...
I have 6 and they are now around 3", but 1-2 of them are still around 2"....
anyways, since my plan was to get a breeding pair i was thinking about that females have more blue on the gill plate but i still find all of them pretty alike..
There is one dominant though (probably a male then?) which is the biggest, darkest and pushes the others around if they get too close.
Here is the dominant:
and one pic of one of the others, they all look alike to me, but this is one of the better looking of the rest:
all of them show similar gill color so maybe its just too early to sex them?