How much to feed?

[TStone23]

I have 2 Green Terrors both are about 2", I've been told they are both male but I'm having my doubts since they both follow each other around, and both are normal in colour now, I was just wondering how often I should feed them and how much. I've been giving them 2 pinches of food at every feeding which is 2 times a day morning and night.