How much light for FW fish (no plants)?

[BEAUCASTLE]

My tank is in a fairly dark place. Do my fish need the lights turned on to be healthy? They are all angels and seen pretty healthy without the lights on on a regular schedule. No plantings to think about.

Any advice?

 

[JPKeenan]

I'm not doctor but I would think they need some light. Maybe not 8-12 hours but I would say at least 2 to 4 hours of light.

 

[mfdrookie516]

fish dont need light to grow.... i have my lights on for an hour or so a day on my tanks without live plants, and thats just so i can see them...

 

[meegosh]

Your fish don't NEED the light to live but they would prefer some sort of a lighting schedule, IMO. I kept my lights on for about 6 hours whenever I had just fish and no plants. I used a timer so that they would be on when I got home from work and would go out when I went to bed. Now that I have live plants I am up to about 10 hrs of full light.

 

[JPKeenan]

I was under the impression that any non-nocturnal creature (including humans) need some light.

 

[BEAUCASTLE]

I personally need lots of light.. actually had SAD when I lived up north. But my angels are from a kind of murky place so I was just curious if there was a scientific answer. They get some light from the room. I was curious specifically about turning on the light over the tank for a certain amount of time.

 

[taylorodw]

I have read that a fish appreciates a natural cycle similar to sunup/sundown. That said, I know humans need sunlight for certain D vitamins. I don't know anything about this topic on fish though.

 

[JPKeenan]

that's what I was figuring too. Granted that fish, mammals, and reptiles all have different needs (not even counting cave creature and the extreme life forms) but all need some sort of light to my knowledge.

Know what you mean about the SAD. Days get short up north!