http://www.ithacareef.com/chromis/index.htm

I've been trying to determine how long before they hatch. I haven't been able to time them yet, but 3 days sounds about right to me. Not sure where they are laying any more. I took the acrylic sheet out of the tank because they avoided it. At that time they were still laying on the glass to the side of it, but I haven't seen eggs there since I took the sheet out. I may have more than one pair spawning. Mine don't concentrate their eggs at the top like this link reports. Their eggs are evenly distributed from top to bottom on the back glass. I don't have the algae as he reports they prefer either. However, they use the back glass that is never cleaned and have never layed on the glass that is cleaned on a regular basis. I think they also lay on the underside of my rocks sometimes.