Ambient Light?

[Oddball~]

I turn the lights off of my tank around 7-8 PM, depending on, 10 PM latest if I come back through traffic.

However, there are usually other lights on in the house, though. You can see the downstairs area and usually the downstairs sends light upstairs where the tank is. Will this stress my little fishies, or will it create an unworked-for moonlight effect?

 

[YoFishboy]

I would think that, if the ambient light level actually reaching the tank is relatively low, and it is consistant, your fish will adjust and develop a regular sleep pattern.