Fan sometime won't help if your room temp is high.

We do need to provide oxygen at night when your tank is kind of new which just setup like example a week or two. (Good to prevent the BGA if you dose with KNO3 and K2SO4 by running air stone at night)

Aquatic plants running photosynthesis when photoperiod and providing the O2 to fishes. But then, they will need more O2 when photoperiod is off. And more CO2 will providing. As well as the bacteria which is inside your tank n filter.