It depends on how bright it is. If it's bright enough to light up the fish tank, it can affect their cycle. Having an unbalanced day/night cycle will stress the fish, much like how it would stress you out. A stressed fish will have a weaker immune system & may be more aggressive or more likely to be bullied by aggressive fish.
If your fish lights are pretty bright, the ambient room lighting (again, depending on how bright/where your fish tank is located) will probably not affect it. In my living room, I keep the lights just over the fish tank off during night and turn on the floor lights on the other side of the room. As long as the tank looks fairly dark, it should be fine!