To get the blue colouration of the elctric blue jack dempsey you ordinarilly have to breed a normal Jack with an EB Jack. I'm unsure whether breeding between a convict and EBJD will give you electric blue fry. The fry will obviously be hyrid in some way but theres no saying how they will come out.
Also getting a Jack to pair off with a convict isnt easy practice as there isnt a general way to make them spawn (i would have thought). Only due to it not being a natural occurence? Generally i wouldnt advise hybridising fish.