I have several colonies, started from 1 about 2.5 to 3 years ago. I don't see any need for light, but as long as they're healthy, I haven't seen them dwindle or get covered in algae, even in bright light. I have noticed many small colonies in the darkness in my overflow. I do feed a lot of small particulate foods, but haven't target-fed them. Moderate to high flow seems good. I also have dosed "Sponge Power" from zeovite, but I'm not sure it's magical or required. I do love the bright blue color.