yep, if you are going the convict jd and pictus route then you should do sand, the jd and oscar will dig, and pictus tend to get shorter whiskers on gravel. i would personally do a tank that is wide and long as was posted earlier, that way cleaning and vacuuming is not such a pita. also set up decor to divide the tank into like 5-7 "sectors" so the fish will not fight as much over teritory.