i wouldn't recommend it, other fish being agressive will only bring out the tru agression of the leichardti... lei's would be better with relaxed fish so it doesn't have to go postal on others.
if u start them real young, there is a chance it could be so tame and calm. mine has yet to show any real agression. but then again its only 6-7". but keeping it with fish that are not similiar in shape/size to its self will help keep him calm. i have mine with rays/bichirs/dats and he's as relaxed as a silver arowana. minds his business and eats all day