Try feeding your frozen foods first thing in the morning when they are hungry. I cut some market shrimp up into bite sized pieces this morning, and some of my little ones gobbled it right up. This was the first time they had ever seen dead food. If they don't go for it, don't worry about it. Feed them your regular food, and try again later. If I were you, I would feed the guppies once a day, or every other day, and feed blackworms, bloodworms, or frozen if they'll eat it, the rest of the time. Live blackworms are great for little ones, they wiggle, and the eat them like they are starving. Good nutrition too. They are one of my favorite discus foods.