They will become a little less aggressive but piranha aren't the most aggressive fish out there anyways.. and frozen food/varied diet is better for them..
they wont really change if there a finger chaser they will be if you feed them live or frozen and if there skiddish they will be shiddish with or without live (they should eventually get used to you if skiddish though)
started 20 % water changes,added a power head, and more there stuff in tank around on sunday, they seem to be mor active now....thanks guys !!!!!!!!!!!!!!!!