Once every 2 weeks IMO. If the lighting is adequate they should do fine. Sometimes they split when stressed (self preservation) and the clones start out at a dis-advantage and need the supplemental feedings, but twice a week is too often IME, they just can not digest it that fast and may expel the piece and you do not see it and it can cause a bacterial problem. You should see an ammonia spike from decay but you may not. Good luck with the fish.