he eats feeder guppies, goldfish and chicken heart. are all three ok for him. well hi im new and and new to piranhas. I own saltwater tanks and this is my first freshwater. also does anyone use black water extract. i am using it and i like how the tanks looks and jaws likes the tank to. he is in a 20 gallon temp tank until i move then he gets a 55 gallon. could i potential get him 2 more buddys for the 20 right now. there only 3-4 inches. quite small. When i get the 55 gallon i want 5 for in there.