Here's what I do: Hard boil an egg. Eat the white and half of the yolk. Hehe. Take a small piece of the remaining yolk, about twice or thrice the size of a rice grain. Put the small pieces of egg yolk in a cup. Put the remaining yolk in a sealed container and refrigerate (should last for about two to three days). Back to the pieces of egg yolk in the cup. Add a tablespoon of water. Mash the egg yolk so that it mixes with the water. Get a medicine dropper, you know how to use it. I feed my 40+ fry around six drops of egg yolk solution twice a day. Haven't seen any casualties yet, and they're all doing great despite the putrid water they were forced to live in for a week. Some are growing rather fast. Be sure to syphon any leftovers. In my experience, Egg yolk can really foul the water. I didn't clean my fry tank for a week and when I had the chance to smell it I almost threw up. Hehe. Good luck.
John