They are coming up and eating. You just don't see them do it. They are going to do it in the dark, when nobody is looking. You won't notice any food disappearing. Springtails are tiny and rice is big. Consider cooking up the entire stock of a McDonald's store and putting it in front of a dozen toddlers. You won't see the thousands of burgers disappearing, but they are eating.I will give it some more time.
I thought they would come up to the surface and eat by now. I thought I was doing something wrong.
I feel a lot better now
Thanks everyone who reply.
For the next few weeks, it's going to look like nothing is happening. Then one day you will lift a large piece of charcoal and see them scurrying away.