Don't Get Fooled between Piranha and Pacu !

Some people get confused of the differences between pacu and a piranha , as sometimes people that are looking for a piranha in a pet store get fooled as they bought a pacu instead of a piranha .
 So here are the differences between a pacu and a piranha is that a pacu have a snubbed face and their teeth are flat , unlike the piranha which have bullet shaped head and razor sharp teeth.                            Heres some pics to show you the differences..