About the black cover I read somewhere to leave on for about a week just have light from the top. I never put a cover on my 1st batch and I did leave the light on all the time and stll have it on. 3rd batch I did cover the out side during the hatch because I moved the rock. I did take it off the am of the hatch. I look at them so much to see if they are OK and if they need more rotifers and if the rotifers need more rotifer diet. I usually do feed the rotifers once a day to keep the water a light green which does make the tank darker so that may have taken the place of the black cover. I'm not sure but it worked for me.
I tried to count the 2 day old fry this am and I think I have around 10-12. I still have 25 or 26 of the older fry. The next batch I think I'm going to leave the rock in again when they hatch. Congrats on your new eggs

