I have free swimmers

I haven't been this excited since my first son was born.

I only count about eight maybe ten. There about the size of the head of a sewing pin with little tails. I tried to get a pick but there still too small.
All the articles I've read say there not supposed to be free swimming until about day five.

It's been 36hours since the spawn.
Nevertheless I made a batch of egg yolk and put a couple of drops in there.
They scattered soon as the syringe touched the water. But were back in the area a few minutes later. So I guess they're eating it.
I am going out of town for a day and a half.
Do you think they'll be ok if I put a couple of large drops?
I'm running a sponge filter only. There may be infusoria growing on it....