Possible dumb question
 

Is there any certain standard for the amount of light you should give your fish, like is it ok for them to be in complete darkness all night and so on? Thanks

Re: Possible dumb question
 

A good reply above. Indeed the intensity will not be all that important for most "fish only" type setups. The important thing will be to replicate some sort of day/night pattern so the fish know when to feed if they are picky. Simple T12 shop lights make good lighting for FO systems.

well to answer your last question. they don't need a moon light (night light) but IMO it will stress the fish out less with a moon light. they have one in the ocean you should give them one. as far as what you can use. in my first tank I used one of my sons night lights from his room. I hung it over the tank. It was one with a light sensor so it turned on automaticly.

JMO

I have read and experienced this for first hand that at least some fish would require the use of light on a regular schedule for their best coloration to show up. I have some goldfish and did not turn the light on for about a month, the room light was on. And they almost became olive. After 3 days of the light on 12 hours a day their color came back and after a week they were bright orange! So it might not affect their health but trying to mimic the environment of the inhabitants is usually the main goal of people trying to keep them. They certainly don't' need anything more than 2 watts per gallon to give them a nice tan.