Yes, always research your fish before buying. I think a 30 will eventually be too small for the Pirhanas anyway. You will start to see them losing eyes as they get too confined and fight.
Balas might have some teeth when young, but most def lose then as they age. They also get very poor vision and mine are now vegetarians.
Anyway, Birch, you posted on the 8th, why did you not take some of the suggestions that people posted?