sorry to say this, it's notthing personal but what i don't understand from a lot of people is that they are to lazy to learn about a fish before bying 1.
RBP need to be kept in groups with a minimum of 3
they need 80 liters swimwater for each single piranha
they need lots of hiding spots
not to much lght
a verry good and heavy filtrasion
so bassicly i hope hope you get a bigger tank soon.
i'm sure you have the best intentions like i have telling you this.