JD, sexing and grow out

[Mekong]

I got 11 tiny Jack Dempseys, I got them at about 2cm, and they have been growing nicely. The biggest one now is a little over 1"

At what size will I be able to tell the sex?

Is it a good chance that they will pair up and mate? In the long run I would prefer to get a EBJD to be a mate to one of these and sell the rest. At what size should I attempt that?

 

[pdbrady]

They'll need to be bigger a couple inches bigger than that to tell. The males will be spangled all over, while the females will have more pronounced coloration on the gill plates. Once you have established sex, I would then try to find an ebjd mate. Otherwise you'll just have to get some of them as well to throw in with the ones you have now and hope for a pairing, and that would get expensive.