hot_boi07;2892251; said:
that's why yours won't shoal together. Gold and gold diamond piranhas are from the genus Serrasalmus. They're solitary hunters that nip the fins off other piranhas. They're parasites. They won't shoal. In fact 90% they eventually kill each other if kept with other members of the same genus. You should put your fish in seperate tanks. Gets some pygocentrus piranha (nattereri, caribe, piraya) if you want to keep more than one in the same tank.
