It is doable but you have to make sure they are both are around the same size. Like someone said a few hiding spots goes along way. If you took the female GT out of your tank and where able to reset her home turf advantage by adding her back in with the male so basicly both would be on level playing feild you should be ok. You could try adding the male to the tank with the female also but you would have to keep and eye on them to make sure one wasnt beating up the other one to bad or they could hit it off just fine. Just make sure you have female and male haha.