so what i did was separated the three new piranhas from my shoal, left the light out cut back feeding, monitored the three new ones who continued to fight. I seperated the trouble maker from the other two. Monitored the other two for a day to make sure they could get along. Then I moved the most docile one pirahna to my tank first, monitored for a day, then moved the second piranha. SO now i have seven piranhas in my tank and i left the troublemaker out of the mix. I also ordereed a 3200 gallon powerhead. Hoping thaqt the water flow will give them something to one do besides chase each other or fight. SO far so good, every seems to be doing good. Leaving the light off has definetly made a difference too. Thanks for all the advice...