My Tadpoles are growing and im not sure how to feed them properly?

I have three Tadpoles, two of them still swim in the water and have legs but no arms yet. My other Tadpole has his legs and arms and doesn't stay in the water anymore he sits on a rock I put in their for him/her. He/she is about the size of a pea and looks just like a frog, what should I be feeding him/her and the other tadpoles? Is the one who sits on the rock big enough to eat small bugs like small worms and potato bugs?