At one time or another every Piranha owner asks this question

I did some other guy did you did , and someone els will . Its normal .
Black Piranha , From the serra family , live alone .
Red Belly Piranha , From the pygo family , can school .
It sucks . But remember.Its like this , I dont like it , the next guy dose not like it.
My exclusive is this , Serra/Black Piranha are like male batta fish ONLY One \
can occupie the tank at one time

Pygo piranha/Red Belly can live with more than one , Its like African Cichlid's
some get a long some do not .

Aney questions ?