I'm not so familiar with the types of live-food used in the States, but I know that Mark Smith feeds his fish with some sort of live worms with great success, but I can't recall their name. Mark, maybe you can shed some light on this?
I feed mine frozen black mosquitolarvae, cyclops, chopped up mysis and newly hatched artemia. In my group some of the fishes will take flakes, while others will not, so I've stopped feeding them flakes as I don't want to have any left-overs. In the spring/summertime I have a barrel outside filled with water, where all sort of insects lay their eggs, and I collect the larvae to feed the fishes. They really love all this tasty crible-crable
Good luck with them!