Taking care of fry is very demanding and an important part of the breeding season but if carried out right it is very rewarding and makes it all worth while.
When the eggs hatch the fry are that small they look like a thread of cotton clinging to the sides, the bottom and the breeding material with their sucker. At this stage they have no mouth or fins, their gills are closed and they are living off their egg sacks. In a few days they will swim to the surface and fill their swim bladders and then they will be free swimming.
(One reason that you have at least a 4 year old female is the bigger the female the bigger the egg, and the bigger the egg sack for the fry to start on).
On day 4 after hatching remove the breeding material. The best will have hatched by now and by removing the rest which are mostly infertile eggs you will keep the ammonia level down.
The ammonia and pH levels are most important and must be kept in check (or you could loose the lot). Since there is no filter running yet and only air stones in the pond, Ammonia and pH must be monitored.
At between 5 and 7 days I treat the pond water and fry with CF 50 to reduce the risk of bacterial diseases and pathogens. At this stage the fry are feeding on infusoria and new born daphnia so no artificial food is required yet.
Now remember that you can not keep all the fry so thin them down to suit the size of your raising tank.
At around day 10 or when you can see the fry chasing and gulping down the daphnia its time to start feeding. There are many formulas but 1 I use at first:-
Boiled egg yoke and Vegemite with a little fry powder in a 1lt of water. Mix in a blender and squirt over the pond.
The daphnia love the fry powder and Vegemite but not too much at first, best to feed a little, 3 times a day.
After a week of this concoction I then go to fry powder. Sprinkle lightly over the surface 3 or 4 times a day plus a dash of yeast. Do not over feed as polution can kill them off. I also feed green water that I have been growing as well as daphnia. Always keep a check on the pH and Ammonia, if necessary do a 50% water change - but treat the new water.
Continue along these lines until they are about 3 cm long, then it's time to add a feeding dish and mix the fry powder and a little calcium powder into a past (not too wet). Roll small amounts into small balls no bigger than a small marble and drop them onto the feeding plate. If there is room, have more than one feeding plate around the pond. Feeding plates sit around 15 cm below the surface of the water.
In about a month after hatching if the fry are of a good size, it's time to start the filter BUT have a small pump not too much volume at first.