Total Newbie with an empty tank

[Tarolisol]

Ive had piranhas before, and they grow BIG fast. a thirty gallon is way to small for them. I had some in a 55g when they were large and one smashed into the side of the tank and cracked it. I feed mine pellets so it didnt cost me much, but i here its hard to get them to eat pellets. I eventully had to give them away since they were to big.