I don't let the lights stay on in my room at night because it's difficult for me to sleep with them on. Similarly, I don't want to disturb my fish's sleep cycle since they're in the same room. I believe keeping the lights on is equivalent to daytime, and since the sun isn't out all day, I prefer to turn them off. Sometimes I turn on the light randomly when I'm up early, but my fish are still asleep. When I do this, the female clownfish appears pale, which I believe is due to her colors adjusting to the light. However, once she is fully awake, her colors return to normal. The male clownfish doesn't seem to have this issue.