How about acually feeding them fish food? sorry I think feeding fish live foods is mean. I may be the onyl one who thinks this, but if your fish are small, why not feed them fish food ?
You do know that fish food is made of fish, right?
The feeders should fit in their mouths. They won't generally go after larger minnows as food, more for a territory thing.
I agree with the guppy idea, or convict fry make a nice snack.