boil up an egg... take the yolk out and mash it up with a little bit of there tank water..strain it threw a fine cloth..like a really fine net and drip a tiny bit in to the tank they will gobble it up.
make sure to not over feed it ill dirty the water quickly, also try getting some blood worms and letting them thaw..dump in just the juice..its what i did for ...2-3 batches of fry and it worked great.
you will lose some to this method some fry just will not take to non living food but..in my opinion the strongest or most able to adapt survive^_^
there are some food for fish fry on the market finely ground up powders ..just take a variety of fish foods and mash them with a mortar and pestle ..( i used my counter top and a flat rock) until its an extremely fine powder.
good luck with your fry