I had 4 red belly piranhas from the same size as yours... 1 got caught in my filter and died so I change md the filter to a much better external then the dominant one turned on the other 2 and killed them both. Now he lives on his own in a 46 gal. He won't tolerate anything else in the tank, and by this I mean other piranhas so no chance of different fish. He is evil. He is around 8-9 inches now
/www.youtube.com/watch?v=VBmeXb0SfFw&feature=plcp&context=C3ee2fc8UDOEgsToPDskLhUtFg7Cj31wA3RIDuVo-v
