I am having a hard time with mine right now. It was in bad shape to begin with (the fish store did not feed it. I was hoping to try to save it). It does not come out at all during the day, and only a few of the heads come out at night (and they don't usually come all the way out). I have been feeding it every 2 days or so (I isolate it and feed it cyclopeeze). The only improvement I have noticed is that the tentacles seem to come out a little further than they used to. I am keeping my fingers crossed though. In terms of light, they are non-photosynthetic as mentioned above. So if they are exposed to strong lights it could harm them. Most things I have read state they should be placed low in the tank and in a shaded area. There are a lot of good posts about sun polyps in the non-photosynthetic section of the boards.