I have a breeding pair of cons...with a load of fry swimming around as we speak
here is what I can tell you, keep in mind, this is what I witnessed with my own eyes with MY PAIR of convicts...this may not apply to all
sexing: my male's dorsal fin extends PAST his tail, and is noticeable longer than the female's
the female has a pink/orange area on her tummy
behavior: my pair seemed to "flirt" a lot, they would chase each other around and often kind of rub against each other
environment: they need a cave or something of the like to lay eggs in
post hatch: I've been told by others to remove the male, some told me to remove both parents, some said to leave them in with the fry...due to not having any other room, I left BOTH parents in WITH the fry...so far so good...I have noticed the numbers thinning a little bit, but not bad...the fry are about 3 weeks old now and I'd say I still have 30-40% of the original brood left...the fry are growing well, they are feeding off of **** off the bottom because they are yet too small to swim to the top to feed
hope this helps
and I am glad you have cons...they're my favorite fish!