i've got 2 of these as well, and they are extremely territorial (you'll hear lots of clicking comin fromt he tank when they fight)
but when i moved them from my 4ft to my 6ft the extra space has calmed this, they dont seem to bother the other fish at all, and on the bottom with them in the 6ft is an assrtment of syno's, clown loaches, skunk loaches, a pakistani loach, a polkdot loach, and various corries and they seem fine.