the female have red, orange spot on the belly and more black stripe. They are smaller compare to male too. To breed them you need a clay pot and put them in a 10g tank. Its best to have them by themselves. Feed them frozen blood worms only so they can breed faster. You need 2 female and 1 male so you get more chance that they pair up.
If you have a male and a female you will only have to do one thing to breed them. That is put them in water. They will take care of the rest. Also, a ten gallon tank is too small for a pair of convicts, too small for them to be happy and thrive anyway.
Females may only have a few orange scales, but males will have none. Males also have dark spots at the base of their tail fin, which females generally lack.