HELP ME! with my crib babies please?

My cribs have been have babies every 6 weeks for the last 8 months. The problem is the babies never survive longer than 5 weeks, they just disappear one by one. Whats the best thing to do to increase their survival rate. Do I separate the fish into a tank on their or separate them from their parents or something different. I would really like to see them grow to full sized adults. And also do i need to do anything else to care for them?