I recently picked up a beautiful rainbow open brain for my new 42g tank - this is my fist brain coral so I'm not totally sure what is normal behavior for a brain. I've placed it on the sand and have a kessil 360 over it. I've had it for a little over 2 weeks now. It opens up nicely during the day and seems happy almost all day long. But a couple of times I've noticed that it retracts about 30m to 1hr before normal lights out. I often feed around this time of day as well, though it does this before I feed and not in response to feeding (and it doesn't put tentacles out for feeding, only at night after lights are out). Is retraction during or near the end of the normal light cycle typical behavior for a brain? Or is this an indication that is is unhappy with the amount of light or length of time it is getting light? I have my lights set to come on around 11am and turn off at 9:30pm. I have intensity setting pretty low right now to give the corals time to acclimate. Any ideas?\n \nThanks!