Only had a couple do the circle thing pretty early on. Haven't seen it since. At this point i have a handful doing the up and down and another handful that have left the nest and are just hanging out and can swim fine. I'll try some EY tomorrow morning or something, and hopefully my friend will be by with the bottle i can use to hatch bbs.
It's making me a little nervous you're asking these questions now after you already have fry, but this is how I feed egg yolk. Hard boil the egg and let it cool completely. Break it in half and scoop the yolk out. Every day, break off a tiny piece and add a drop or two of water. Mash it all up until the egg is thoroughly mixed. Suck up a few drops and drop them in the tank where the fry are. The egg should be mostly floating on the top where the fry can get it.
However, since you have a lot of creepy crawlies in your tank, I would just eye them. Egg yolk is dirtying and you'll be able to see if your fish are eating the critters by their big white bellies. If they are, no need to add egg yolk yet.
Egg yolk: hard boiled - longer boiled, better
Take the yolk only, you can eat the white stuff.
Take a tiny pinch of yolk and ;
a. squeeze it around the water surface
b. dilute it in a cup of water and carefully pour evenly in the tank.
c. dilute it (more than a pinch) in a small spray and spray evenly on the surface. Refrigerate the remaining EY solution.
Freeze the rest for later use. 1 yolk can be used for a lot of spawns.
If the water gets cloudy, you're using too much. 1-2mm per feeding is enough
I agree with GT, if your tank is full of micro critters, you don't really need EY. But if you want, you could feed EY once a day.