If they will eat it thats fine, haven't had any luck getting pups to eat shrimp or tilapia. I feed blackworms to get them started and then chopped nightcrawlers.
Redbellypiranha: She had four pups in a 330 gallon tank. The pups are now in a 53 gallon tank - Their home until I sell them when I think they're big enough and the right home is right in front of me
By looking at the pictures you have i am now certain that mine were earlyborns, lost them both after 2 months. They didnt seem to eat, so i was a little surprised they keept it going for so long.
Yours look beautifull and healthy! Good luck with them in the future!