I dont believe it matters about the lights untill "after" they lay eggs. From the research I have done the parents are more likely to mistake the babies for food if the lights are off. Also the eggs may be light sensitive as well. But also the effect of having the lights always on can effect the overall coloration of the fish as well. Theres a article on another forum that gets in depth on genetics, like pages and pages. I can't remember where it was. If I find it I will post it. Anyways To get around having the lights on all the time I dimmed mine with screens over the glass that the light shines through. Or you could invest in moon lights.