The goldfish will get more oxygen in the day, but at night, they will be competing for oxygen.
Yes, it is possible.
A cloudy day may lead to thunderstorms. Since water conducts electricity, it is especially dangerous to be in water if lightning occurs. Another reason: Even though it is cloudy. UV rays that cause sunburn can get through. You still need to apply sunscreen to prevent sunburn on cloudy days.
sunny day or a clear day
a simile for a cloudy winter day
the effect of a cloudy day is it might rain.
A cloudy day is when the sky is full of clouds which block out the sun.
The interrogative is below: Is it a cloudy day?
Change its water every day.
warm sunny day
"Overcast" is the correct summary for a cloudy day.
Pumping air will have no effect on the poisons in the water that are making it cloudy. If you don't change the water pretty soon the fish will die. Goldfish bowls are not and never have been suitable containers for keeping fish in. This was done in the 1800s in ignorance of the requirements for keeping fish alive. It has been common knowledge since the early 1930s that GoldfishBowls are not suitable for keeping fish in. In this day and age there is really no excuse other than greed for pet shops to be selling these horrible fish torture chambers. The first rule of fish keeping is "1 inch of fish needs a minimum of 1 gallon of water.