can 2 pairs of percs or fake percs live in a 55 gallon tank that has about 90lbs of live rock if they are the only fish in the tank. never tried more than a pair at a time, i know they are aggressive towards their own and even more so when they start spawning. i have a pair right now, would it be ok to add a couple of young percs to the tank or are they doomed by the 2 that have already paired up?