You'll always have fun nipping and aggressive play and sometimes disputes with reds. The point of being the caretaker is to really focus on minimizing this. 65 gallons may seem like sufficient room right now, but they'll quickly fill that in. The three things you'll want to focus on are lighting, water quality and diet. Dimmer lights will calm a piranhas nerves and ease stress. Water quality goes without saying. Diet should be less live food and more stable healthy dried, frozen or fresh aquatic foods. White fish, shellfish and the like make a wonderful meaty source for them. 'Feeders' are really a pretty poor source for anything.
As for the missing fins, they will regenerate unless the entire tail was taken off. In that case it will heal over and the piranha will live with a battle scar for its life.
As for the missing fins, they will regenerate unless the entire tail was taken off. In that case it will heal over and the piranha will live with a battle scar for its life.
