I have a 180 gal 6x2x2 current stock is a tire track eel, 2x eclipse catfish, jaguar cichlid and a pike cichlid. Just wondering if there is any species of knife fish that would work with this combo. Black ghost knives and Brown knives are available to me regularly. Is my tank already over stocked? if not will the jag be too aggro for a knife? the jag is smallest in the tank maybe 1inch and half. So its too small to sex.