so im looking for people who have had or do have african tigerfish, and black piranhas, and elong piranhas. i personally have had black ps in the past and they are super territoral once they get about 6' or more but a little skittish. ive never had tigerfish or elongs are the a one fish per tank fish like the blacks or can they e kept with anything are thwy skittish and are the very active and at what gsize do they become territorial?