ha again thanks for everyone's feedback and i do have a fifty five gallon tank at my parents i am strapped for space in my apartment. if i could swing it i have a friend who would give me a sweet hundred gallon tank. but unfortunately i do not have the room. for now i have to stay small and work up from there. i shall keep doing research and go from there.
so these are all good ideas. and i would love to set up the 55 or even the hundred gallon tank but my apartment will just not fit those. plus i do not think i could convince my girlfriend of it either. so for now and until we can afford the a larger place the 20 long will have to suffice.
you could build a stand for both of them (20 long on top and 20 on bottom) then have exodons in the 20 long and a pair of convicts in the bottom, convicts are really cool cause you get to watch how they take care of their babies and then you could feed the babies to the exodons so you are not completly overstocked with cons lol