They should eat as much live food as they want within 10-15 minutes 2-3 times a day at that age. You should offer greens daily, although he probably won't touch them at first. He will get the idea that it's food one day though! It is important that he sees veg now and gets used to it, he will give it a try eventually!
my adult beadie eats about 10 crickets in one go then he turns his noes up at them later in the day, he gets served greens every day all tho when i first got him i think he didnt know what it was lol he dont eat greens all the time but he does enjoy it when he actually eats it :2thumb: i would just keep putting some in what i did was give him a cricket then wiggle a bit of green in front of his face and eventually he just took it