Answer:
The easiest way is to boiled an egg and then take the egg yolk to make it into liquid fry food. Take a very small piece of egg yolk size of rice and mix it with water. Stir it until it becomes debris which the fry can eat easily. Let the egg yolk particles be as smaller as possible. Feed then egg yolk until they get to 2 weeks old and above. On the 3rd week, let them have bigger food such as BBS, Microworms, bloodworms and so on.
Warning: Egg yolks can be a good food for fry with high protein. It actually help them grow faster than what we can imagine. HOWEVER, be caution with the water quality. Egg yolk tend to make the water cloudy and the bottom gets really bad with lots of fungus going on. Make sure you siphon any left over food every each meal. Otherwise, you will only see one by one die.
P.S. Fry will eat anything they saw. Even a rotten egg with fungus, they would eat it. So pay extra attention on this.