they are still small i would say feed them live for a little for a little while till they gain another inch or so.. feeders are bad but also good, do you think every fish they eat in the wild are healthy?! i highly though that since most fish eaten are the slowest ones... anyways what is your water temp? keep you tank at the lowest of 87 degrees and parasite can not host so you won't have to worry about anything. you should then be fine, i never had a problems. minnows, tubilex, black worms, the more variety the better.
as for how much you should feed them, people stuff their cichla, i disagree with this... feed them 2 or so small/medium sized meals a day and do lot of water changes, it is deff healthier for the fish. when ever i stuff my fish one always gets sick.