i figured so, keeping them in a 6 by 2 for their entire lifetime is not a smart thing?
No it isnt

Youll need at least a doble in all directions and that is only for one. This guys get BIG. Even if most are smaller than their wild conterparts they are still huge by aquarium standarts. A 45-55cm animal is to expect.
I have a pair and i know they can be agressive towards each other but the person i bought the pair from said they have been living together up until now and had no problems fighting n think they r male/female pair...
First of the people you brougth them from is lying because there is no way to sex them at this size. It will take years untill you can make a good gess and even more time untill the secundary sexual caracteristics became realy aparent. By the way start praying that you dont have a female as she will need a big moist sandy area in wich to lay her eggs in about 22 years or so

That can be acompanied by medical trobbleship
Also is comon for territorial animals to behave in a no agressive maner when they are in pet shops simply because they are stressed and still trying to settle temselfes. But once setled they can became agressive. If I were you and dont wanting to risk both animals well being I would keep them apart.
so far i havent seen any wild vigorous actions but i dotn wana risk the worst outcome...but im sure there are ppl who successfully mixed these and had no problems??? anyone out there like to share this??? i dont wana sell one off because of their health hazard...