I wait a minimum of 3 months before releasing my newborn fry. I find they reach the perfect-non-eating size by then, but still leave refuge for them b/c some bigger fish will nip and chase them b/c they're smaller.
I scoop them up in a dixie cup(i don't like netting b/c it damages their slime coat) and slowly add water in from the adult tank.after 15 mins i tip the cup on it's side and let them swim out on their own. Include floating plants or plants by the surface since thats the majority where the fry will reside. When they get more comfortable, they will explore the tank later.
I do agree with Zenn, you should feed the adults and other fish. It will be alot easier for the fry when they enter.