# Do fish need a day cycle?



## UnderseaGal (Mar 4, 2014)

I'm told not to let my tank light on for more than 10 hours/day to limit algae growth.

I'd love to just be able to turn the light on when I'm home (a few hours in the morning, a few hours in the evening).
Do fish need a day cycle that mimics ours? Should the light always be on at the same time and only get turned on once a day?

I apologize if I'm asking questions that were already asked - please feel free to point me to a thread if that's the case.
I always do a search first but don't always find quite what I'm looking for!

Thanks so much for any insights on this!


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## jhj0112 (Jul 30, 2013)

it depends on if you want to keep live plants or not.. plants need regular light time.. as for fishes.. as long as lighting time is done regularly, they will be fine. When I was on vacation for a week, both apisto tanks and pea puffer tank's lights were off during the vacation. they were scared when I turned on the light at first but they are fine now.. 

IMO, 10hr/day is way too long.. I put my lighting time around 6-8 hours using timers.


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## onefishtwofish (Apr 21, 2010)

I always have the lights on when i feel like it because after all, the fish r there for my enjoyment. on the other side tho I know they need to sleep too so I try not to leave them on too long. I was also told that africans color can be affected by too much light. I dont have plants and my plecos take care of any algae so that is not a factor for me.


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## UnderseaGal (Mar 4, 2014)

Thanks jhj0112 and onefishtwofish (love the name!).
I guess the light is more important for the plants than for the fish. I have 3 small plants in my tank, 2 java ferns and another one I don't know the name of.
Will the plants be ok if they have 2 periods of light/day that amount to about 8 hours? Say, 2 hours in the morning and 6 at night?
Or is it bad to break it up like that?

-J


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## Fish rookie (May 21, 2012)

UnderseaGal said:


> Thanks jhj0112 and onefishtwofish (love the name!).
> I guess the light is more important for the plants than for the fish. I have 3 small plants in my tank, 2 java ferns and another one I don't know the name of.
> Will the plants be ok if they have 2 periods of light/day that amount to about 8 hours? Say, 2 hours in the morning and 6 at night?
> Or is it bad to break it up like that?
> ...


To break up the lighting period according to some studies is actually good for avoiding algae.
What does your other plant looks like?
If it is only java fern you don't really need much light, it is a very easy to grow plant and is very hard to kill. I have tried them with only 4 hours of light a day and they were fine. Too much light will cause algae to grow on their leaves.
Not sure about your other plant. It if is a red plant then you probably need to give it much more care. Some plants are hardy and some even need CO2 injection to thrive so it is hard to say.
Your java fern should be fine with 2 hours in the morning and 4-6 hours in the evening. 
Buy a timer, if you want to, so you can just control when the light comes on and off automatically.
Don't worry, I think you will be fine. I would suggest to start slow and take things one at a time. Don't add too much too soon. 
It is a small tank so keeping things simple and minimal will likely look better anyway, in my opinion.


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## UnderseaGal (Mar 4, 2014)

Thanks Fish rookie! That makes sense. I know both plants are supposed to be easy to keep, so I shouldn't stress out too much.  Haha I guess I had a bad experience previously so this time I want to make sure I get it right!

I don't plan on adding anything for a while. The only thing that I might add down the road is a betta or another solitary fish. It does feel like the tank is missing something. But I'm in no rush.

I'll post a picture in the photo thread - maybe someone can identify the plant.
Thanks again!


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## dino (Aug 29, 2011)

In my opinion lots of creatures including ourselves enjoy a scheduled and consistency. A day and night cycle is more enjoyable for your fish but can be shortened and not needed but I always try to simulate nature


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## Steve (Mar 27, 2013)

I use a timed light cycle and keep my lights on for around 14 hrs a day and have very little algae growth


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## 2wheelsx2 (Apr 21, 2010)

I run a timer and have several of my tanks turn on the lights for the 2 hours I'm around in the morning and then another 8 hours from afternoon to about 11 PM. The fish can pretty much get used to anything. The main thing is to avoid too much light so you don't run into algae problems. Some people I know run a 12 on 12 off cycle to simulate the equator for breeding, but that's for a specific purpose.


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## lonewulff (Feb 5, 2014)

Steve said:


> I use a timed light cycle and keep my lights on for around 14 hrs a day and have very little algae growth


Hi Steve, to what do you attribute your "very little algae" with "around 14 hrs" of timed light?

B. AIT (aquarist in training)


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## Fish rookie (May 21, 2012)

From reading Steve's posts it is quite obvious to me that he is very experienced and knows a lot about fish keeping. He probably keeps his tank very well balanced hence not much algae. 
I like the B.AIT bits.


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## jbyoung00008 (May 16, 2011)

I agree with the above. The lights should be on a timer. Mine come on for an hour in the morning before work. Than 8hrs later in the day. I do a sunset/sunrise with 2 timers. It might be overkill but Im sure its easier on the fish's eyes.

I posted an article awhile back on fish eyes. Here's what the author says.

"Fish lack eyelids (although sharks and some other fish have a nictitating membrane that they can close over their eyes to avoid mechanical damage). Fish also seem to lack a rapidly responding iris to quickly limit the amount of light entering the pupil. For these two reasons, fish are unable to adapt to rapid changes in light levels, and some species may react to such a change by going into systemic shock if the light level changes too quickly. Since this shock reaction cannot easily be predicted by aquarists, it is always best to slowly ramp up the lighting in an aquarium so the fish are not startled by a sudden change in intensity. Additionally, since they do not have eyelids, diurnal fish (those active during the day) should be given a mostly dark aquarium at night so that they can receive a proper amount of "down time" that functions as their sleep mechanism. Although fish can survive under "24/7" lighting for long periods, (personal observation) it is prudent to avoid such constant lighting in order to reduce overall stress levels in the fish."

Aquarium Fish: The 'Eyes' Have it: A Review of Eye Health in Aquarium Fishes â€" Advanced Aquarist | Aquarist Magazine and Blog


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## UnderseaGal (Mar 4, 2014)

Thanks for this detailed info, jbyoung00008.
This makes sense - this morning when I turned my light on my fish seemed stunned - I'll see if I can rig a gradual lightning thing.

Happy to hear a hour or two in the morning is ok, though - I just can't wait to look at the gang when I wake up! 
Thanks again!


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## jbyoung00008 (May 16, 2011)

UnderseaGal said:


> Thanks for this detailed info, jbyoung00008.
> This makes sense - this morning when I turned my light on my fish seemed stunned - I'll see if I can rig a gradual lightning thing.
> 
> Happy to hear a hour or two in the morning is ok, though - I just can't wait to look at the gang when I wake up!
> Thanks again!


A good rule of thumb is to have the lights on for a 1/2 hr before feeding for the reason you noticed. Fish can be stunned when the lights are turned on. So waiting a bit for them to adjust, than feeding is a better idea. You will notice that if you turn the lights on in the morning and feed right away, a lot of the food will get missed by the fish. This will cause more waste in the tank and more maintenance for you.

If you have multiple lights its easy to buy 2 timers and create a sunset/sunrise. If you don't have or want multiple lights than adding a moon light/s may help with the light transition


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## UnderseaGal (Mar 4, 2014)

Thanks for that tip regarding feeding. Very good point!

Ps Your 125g tank looks amazing!


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## Steve (Mar 27, 2013)

lonewulff said:


> Hi Steve, to what do you attribute your "very little algae" with "around 14 hrs" of timed light?
> 
> B. AIT (aquarist in training)


Well, I have 3 timers on 3 different lights that are all slightly different just due to manual set up so that's why it's approximately 14 hours and I kept it at that length for my own personal pleasure. 1 tank has 3 BNP and 1 tank has 1 BNP and I rarely ever need to clean the glass in part due to the plecos but also just due to the fact that not much algae has grown. My tanks are also overfiltered and not overfed which helps keep algae at bay.


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## AKAmikeross (Nov 5, 2012)

I don't have a set schedule/timer on my lighting. My fish get a natural sunrise everyday because the tank is close to a large window in my master bedroom. I get home from work pretty early 3pm and turn the lighting on. I feed them and the light stays on until the late evening, switch to moon lights only on for an hour or so, then lights out completely when I go to sleep.

Come to think of it my fish only get complete darkness for about 6-8 hours... is this a bad thing? Do they require more darkness in a 24 hour period?


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