The flakes are good enough for them. Just make sure to feed them frequently so they will grow as fast as possible. They should be big enough to be safe from being eaten after two weeks.

I would leave them until they are twice the size of the danios' mouths. My platies always took much more than two weeks to get any size on them.

I have about 20 swordtails fry and 10 platy fry in 2 breeder net on last January 2009. I kept them in breeder net-multi purpose breeder for almost 8 weeks. I cleaned the breeder net about once every 10 days and feed the fry sparingly with Baby Bites 3 times a day. Ground up fish flakes would be fine too. On March 2009, I finally decided to let the fry out of the breeder net and let the nature do its job. I have 3 good size Giant Danios in the same tank at that time. I feed the other fish before letting the fry out. Shortly, I have 14 left and they are doing very well and healthy. You can also provide lots of plants for the fry to hide. Good Luck with your Platy fry.

Nat