Please visit our Sponsors
FAQs about "Moon" light for Marine Systems

Related Articles: Marine Light, & LightingMoving Light Systems

Related FAQs: Lighting Marine Invertebrates Coral System LightingSmall System Lighting, LR LightingTridacnid Lighting

One use for such lighting is to enjoy nocturnal activity... by you! Meandrina meandrites at night in Bonaire.

Re: Whether or not to moonlight?...     12/16/19
Moonlight follow-up question…
The only practical place to install a moonlight at the top of my 220 gallon reef is right in front of the overflow. My question is... will I (inadvertently) just be 'luring' all of my copepods and amphipods to their
death, courtesy of a trip directly to the skimmer if they try to swim into-the-light?
<Possibly they will go through the overflow, hard to tell. Do you have copepods in your macro algae sump?... I’d try to establish them there, they will grow quite well and only a part will reach the main tank to constantly feed your livestock. Wil.>

Lighting in the night....11/10/11
Hi guys first time writing have read so much useful info on this site you guys are a credit to the hobby.
<Hello Leon, and thank you.>
I am currently in the process of setting up my first marine tank 'freshwater convert' and I have a question regarding lighting I will be using four white t5s and two blues for my normal lighting during the day and like the look of the blue at night but obviously it's not a good idea to leave blues on too long after whites switch off would it be ok to use a t8 light 39w for the night my tank is 260 litre it will have sump 75l approx, fuge 45l approx, skimmer, uv light, Chaeto, live rock and DSB in main tank and fuge thanks in advance and keep up the great work.
<Be better off using one of the LED stunner strips. They are relatively inexpensive and work well for this purpose. James (Salty Dog)>

Under the moon light - 8/1/10
Hi WWM Crew:
I am sure people tell you guys that what great service you have provided for the hobby, and how helpful you have been to us fish keeper, so I won't tell you stuff that you already know. Here is my question; I would like to install some color moon light for my 75g saltwater fish tank. It now has one Clown fish, two Bartlett Anthias, one Blue Damsel, one Royal Gramma and four Bubble Tips Anemones. Are my fish color blind?
<Mmm, no... their perception of colour is a bit different from ours, but they can/do perceive>
Does it matter what color of moon light I install in my fish tank?
<Really much more a matter of your preference than theirs... aesthetically or functionally; as long as it's "not too bright">
The most popular color is blue, but I would like to install some purple ones, does it matter?
<Not much, no>
I read it some where that blue moon light are suppose to help with my life stocks nocturnal cycle, is it true?
<Well... sort of. Of more use to help all see a bit if the room the system is is too dark>
Will purple moon light does the same thing? Thank you for your time and info.
<Matters little... Read here: http://wetwebmedia.com/moonlgtgfaqs.htm
Bob Fenner>

Moonlights  6/8/10
Hi Crew --
<Howdy Sean>
I recently went to a LFS to get some recommendations for moonlights. My tank is 72x24x29 (220g), so they recommended 2 stunner LED strips to provide full coverage. I went to the website for the stunners
<I do like this brand/manufacturer>
and they didn't list these for night use.
<Mmm, can be>
I gave the stunners a try, and the effect is quite nice, but I wonder if it's too much light to run at night or if it's even the best kind of light.
<Is not too much light>
I couldn't find many FAQs or articles on WWM for this, so my questions are as follows:
-- The 2 stunner strips are each listed as 24V 453nm Actinic Blue. Is this too much light for night use?
<Is not>
Do you have any guidelines for how much light is appropriate for night use?
<Mmm... in candle power, Lux, lumens? I do not... other than a/my subjective evaluation, having dived a good many times about the world, often at night. At times it's "quite bright">
If it's too much light, I could think about putting a piece of colored (blue) acrylic (or perhaps some clear acrylic with window tinting added) between the stunners and the water to cut down on light...
<In looking at Ecoxotic's site you link above, I don't see where they state these lights are dimmable... they should be... I'd contact the maker if you have such interest. Do note that the units are only 12.5" long, with a 6" intermediate/joinable cable... so the majority of the run of your system will be much darker... So... I don't think there's an issue here using these lights as is>
-- Is actinic blue OK for night use without any white?
There are other specifically moonlight products (e.g., R2) that seem to use blue LEDs only, while Current USA offers both "Moon White" and "Nocturnal Blue" color options. Is actinic blue the same as the blue that would be
included in blue LEDs designed specifically for moonlight use?
<Mmm, could be, yes. The wavelengths, narrow band-widths are close/similar>
-- I saw one WWM FAQ that mentioned that moonlights should not be on all night,
<Not really a big deal... as long as there is "some light" in the room, this functionally (for the livestock) is fine. The moonlights are for human use/appreciation>
but it didn't mention how long or for what period of time the moonlights should be on. What do you recommend?
-- Some moonlights sold (e.g., R2, Neptune) offer controllers to automatically change brightness with the phases of the moon. Do you think there's much value in these controllers, or is it just as good to have a constant brightness?
<Likely there is some small benefit to such controllers, but again, not necessary... Is this clear, complete to you?>
Thanks for you thoughts.
<Welcome. Bob Fenner>
Re: Moonlights  6/8/10
Very clear and complete. I wanted to be sure I wasn't stressing my fish by running these all night. Thanks for putting me at ease.
<Glad to share! BobF>

Lighting Question'¦Moon Lights OK? -- 03/15/10
I have a 150 gallon salt water tank. I just installed a Coralife lighting system that has dual timers to replicate daylight and nigh time. At night, there are "lunar blue moon glow LED lamps" that are on from 9pm to 9am. Is it OK to have these "lunar blue moon glow LED lamps" on during the night or should there be a period of complete darkness?
<<The 'moon lights' are fine to use, and better than simply plunging the tank from bright light to total darkness. Although there are certainly dark periods from time to time'¦as Bob has noted before, the reef at night is often quite 'bright'>>
Thank you in advance for your reply.
Stephen DeFilippis
Wayne, IL
<<Happy to share'¦ Eric Russell'¦Columbia, SC>>

LED Moon lighting 12/16/09
Hello WWM team,
<Hello Dave>
as I am very very new to salt water aquariums I am interested in your thoughts and comments on the idea of LED blue moon lightings.
<Purely aesthectical, of no use for plant/coral growth.>
<You're welcome. James (Salty Dog)>
Dave Woo

Moon Lights (RMF, input?) 09/24/2009
Is there any documentation regarding the need for total darkness for fish to "sleep"? I have been told my moon lights are not allowing my fish to properly sleep. I could put them on a timer if necessary (the lights, that
is) :).
<Not that I know of, and my fish at least have never been affected by moonlights. My thoughts are that as long as the lights aren't ridiculously bright, it shouldn't be a problem. Might even promote breeding or other metabolic processes. Think about it: the moon usually shines into water at night; it's a fairly natural thing. Will N.>
<<Don't need total darkness... it's surprisingly bright at night underwater on most of the world's reefs. RMF>>

Re: Moon Lights   -- 09/26/09
<Thanks. That was my thinking as well, but I'm still learning from others with more experience.
<Always a good thing.>
The total darkness position seemed a bit extreme to me.
<Agreed, please do pass on this knowledge to whomever talked to you in the first place. Moonlights can actually be of significant benefit, not to mention the coolness-factor.>
<Will N.>

Moonlighting/Tang Selection -- 05/05/08 Hi, <<Hello>> Guys, what do you think about moonlight? <<As in how it relates to aquaria I presume'¦it can be a nice effect, but is hardly a necessity'¦in my opinion>> Is it a necessary to have it or it is just a marketing deal? <<Some folks claim it induces 'spawning' in fish and corals'¦ I do think it can be useful re not plunging the tank in to total darkness when the lights go out, thus affording the fishes a chance to find their nocturnal accommodations. But I don't think it is a 'necessary' option>> I am thinking about my last fish in tank, what do you suggest amongst tangs that I like (sohal, japonicus, leucosternon ....)? <<In my opinion, Acanthurus japonicus is the hardiest and most suitable of the three for your tank'¦with A. leucosternon being a better choice over the Sohal>> I have regal tang, yellow tang, 2 x percula, 2 x convict blenny, 1x Stenopus and 1 x goby in tank 130x50x50 cm. <<Adding another Tang is pushing it, I think (It would be better to 'replace' the Regal Tang)'¦and will certainly mean no more fish additions here>> Thx in advance, BR/Petar <<Happy to share. EricR>>

Nighttime Reef Conditions -- 03/18/08 Good morning. <<Late afternoon now/here>> Howzit? <<Not so bad, thanks>> I just have a quick question concerning night time on the reef. <<Uh-huh'¦heard that before [grin]>> I've tried locating any guidelines, rules, do's and don'ts on what the conditions should be for the reef at night. <<Mmm'¦is likely not 'spelled out' somewhere, but would/does require a bit of researching/keyword searches on the NET in general re>> By conditions I mean water flow mainly...and also lunar light. <<Okay>> Here's what I got for flow during the day....AquaClear 110, Remora Pro with Rio 1400, and the Koralia # 4 (1200gph). <<I see>> I mainly will have SPS (only one little guy right now). The Koralia does wonders for water movement. The polyps on my Acropora show a very intermittent and random flow on them. Very pleased. <<Excellent>> Anyways...back to the question.....obviously the filter and the skimmer stay on at night. But should the Koralia be turned off at night? <<Depends'¦ A coral's ability to feed on a wild reef is governed by the volume of water that flows past it. This may be a moot point in many hobbyists' systems due to the lack of available planktors for the corals to feed upon, but if you have a mature plankton-generating refugium plumbed in-line with the display this is likely more of a factor as the corals in your system are probably actively feeding after lights-out (I know mine do). Another consideration is the fact oxygen levels drop and CO2 accumulation increases when photosynthesis stops after lights-out. I do think 'some' periods of low flow are natural and restful'¦but not 'too low' and not for 'too long' (e.g. -- A trickle of flow overnight'¦especially if you are not running a 'tropical' lighting cycle of at least 12hrs. with the lights on). My dive time on tropical reefs has admittedly been limited'¦but I do know there are times when you can quite leisurely putt along with little effort'¦and other times when you can kick your butt off and get nowhere'¦even at night>> Are conditions on the reef at night a LOT calmer?? <<Not as a 'rule.' Though this seems as 'natural' to us (being mostly diurnal creatures'¦as are many/most of the fishes we keep), but there are a host of nocturnal creatures that 'come alive' when the sun goes down, and depend much on the currents to carry food/oxygen/et al>> With the Koralia turned off...I get low-med flow but there is a big difference. <<Indeed>> The Koralia really makes the 72g tank move. So, if you guys could help me out on how to have the proper flow for night...that would be great. <<It is my opinion that a good option is to have the flow devices on timers (excluding filter/return pumps, skimmers, and the like)'¦and have the timers programmed to produce short periods of low flow (say, a couple hours at a time) by reducing the number of flow devices in operation but keeping enough flow for adequate gas exchange (possibly provided by the fore mentioned filter/return pumps). The more flow devices you employ, the more possibilities for variation you have at your disposal>> Thanks for all the help in past and present. <<A pleasure to share>> PS. Lunar lights are purely aesthetic correct? <<The lunar cycle (including associated changes in moon lighting) do play a role in spawning and migration in the wild'¦but for the more practical purposes of the aquarium; yes, is primarily an aesthetic touch. Though in the absence of Actinic or some type of dim fluorescent lighting provided after the main lights go out, the presence of 'moon lights' can provide a visual cue to fishes that it is 'time to seek out a place to sleep''¦as well as a bit of illumination by which to find their way there. Regards, EricR>>

Moonlite Replacement for Custom Sea Life Fixture 2/22/08 Again, thanks in advance for all that you do to further the cause. I am now just four years into the hobby and still enjoying it immensely......although there have been times.....! <There always seem to be those times that try us!> I am hoping that someone knows how to get a replacement for the Moonlite feature on the Custom Sea Life PC fixture. Mine is a 48 inch that has 5 moonlights. All but one has burned out. I tried Marine Depot because they sell the Current Orbit which, for the most part, is the same thing. However, their moonlights are individual and the CSL fixture used a "board" with all 5 lights in one unit. I really miss my moonlights but it looks like I may have to do without them. I know there are a lot of individual units out there but I don't really have anyplace to mount one. I don't think there would be room to put one in the CSL unit anywhere. <Other than retrofitting one of the other units as you mentioned, you will have to replace the stock unit. Unfortunately, the manufacturer has gone out of business from what I understand. Championlighting.com was handling their warranty/parts services, but this was a few years back. You may want to contact them to see if a replacement part is still available.> Also someone told me that you can damage a coral if it is directly under the LED because the light beam is too concentrated. I didn't think those particular LEDs have enough intensity to cause a problem. <Mmm, no, they don't.> Any guidance appreciated. Thanks. -- Janie <I hope you can find one, good luck, Scott V.>

Lunar Lights and Coralline Algae -- 02/04/08 Hi, <<Hello>> I am trying to pick the proper light fixture to help grow coralline algae. <<Hmm'¦best to concentrate on providing proper lighting for your corals needs (assuming you have these). If your water chemistry is as it should be, the Coralline will come>> Both fixtures come with 1 daylight lamp and 1 actinic. But one fixture has a white lunar light and the other has a blue lunar light. Will the color of the lunar light make a difference? <<No, the lunar light will have no impact'¦pick the one that is more aesthetically pleasing to 'you'>> I don't want to overdo the blue. <<You may well be, though not as a result of the lunar light color you choose. But without more info re these lighting fixtures and your tank and its inhabitants, I'm unable to comment. But then, maybe your wish was to only inquire about the lunar lights [grin]>> Thanks, Danielle <<Happy to share. EricR>>

Re: Lunar Lights and Coralline Algae -- 02/04/08 I don't have any inhabitants yet, only LR. It has just finished curing. <<Ah, I see>> I wanted to work on the coralline algae before introducing inhabitants. <<Mmm, yes'¦a good idea to let this and other 'emergent' life in/on the rock; along with the many desirable mini- and micro- food organisms, to develop/obtain self sustaining population levels before the introduction of macro-predators>> I purchased a Coralife fixture that will provide me with 2 watts per gallon b/c I have no plans to introduce corals (too much work) except maybe some mushrooms that can handle low light. <<Okay'¦ This simple/small two bulb fixture will likely be fine for this purpose>> Is this an okay approach? <<Should be fine. And based on your data here, you may even want to consider exchanging the 'Daylight' bulb for one with a color temperature of 10,000K'¦though this is not a necessity>> Your advice is greatly appreciated. <<Do let me know if I can be of further assistance as you continue forward with this tank. Regards, EricR>>

Moon Lighting 8/25/07 Hello to all, <Hi George.> Unbelievable site. So glad that I came across a group of individuals that understand the TRUE science of tank husbandry. I get picked on at work for always having the site up. I have searched the FAQ's but cannot find what I am looking for. So here goes. Is there a specific rule of thumb for how long lunar lights should be on? <Nope.> Shouldn't there be a couple hours of total darkness? Given the real lunar cycle ie. Full/ Waxing/Waning/New should there be a few days of no lunar light? If so do you know of any timers that can be set to mimic these conditions. <George, the lunar lights are for the most part, aesthetic. I believe it helps a nervous fish by being able to see the surroundings at night, a calming effect. As far as answers to your other questions, really makes no difference. I do not know of any timers that would duplicate this. The X10 controller (PC based) could be configured to do this. Most Radio Shack stores handle the X10 system.> Thanks <You're welcome. James (Salty Dog)> George

Night Light/Moonlight -- 07/08/07 Hi WWM Crew, <Hi Alan, Mich here.> I was thinking of putting a set of LED lighting to act as night/moon light. Advisable? <Shouldn't hurt.> Will it cause stress to my fishes? <Unlikely.> The reason behind is that whenever I'm back late and the tank lights are off (tank just beside main door), my fishes will just dashes around and caused body injury. <Hopefully this is not the case, but is a good enough reason to add the LED in my thinking.> Thanks in advance. <Welcome!> Regards. <Cheers, Mich> Alan

Re: Night Light/Moonlight -- 07/09/07 Hi WWM Crew / Mich, <Hello again Alan.> Thanks for the reply. <Welcome!> Another question is do fishes actually sleep at all or they just simply rest? <They do sleep, but not how you or I might. I think we would consider it more of a resting state.> Thanks again <Again you are welcome!> Regards. Alan <Cheers, Mich> Cold Cathode Lights for Moonlight? 1/20/07 G'day guys, <'Allo, Glen!> I have a little question for you about moonlighting and have not really been able to find the answer on this site or others. I have a 4ft tank (approx 50 gallons in your US measurements I think) that currently only has 4x 30w fluoro tubes over it. I have a couple of corals in there that are doing ok but really need to upgrade the lighting a bit. Was thinking of using 4x55w T5 tubes for this purpose. The thing is that I was also considering moonlights for my system and the manufacturer of the quad T5 unit also has a product incorporating a moonlighting system using cold cathode lights. I was wondering whether these would be ok over the tank of a night as I have noticed that most (or all) other discussions of moonlighting have been in regards to LED's? <I haven't seen one in practice yet, but what I read and see ( http://www.reefcentral.com/forums/showthread.php?s=&threadid=976028 ) looks pretty good. Moonlighting doesn't have a "standard" to follow, just dim, non-photosynthetic-stimulating intensity and you're set.> If they are ok, the housings contain two of these tubes, what length tubes would you recommend? <I am unfamiliar with the product, but I think "size matters not" in this case.> I thank you very much for your time, you provide an invaluable resource that I often spend hours in front of. <Great to hear, Glenn. I still find great treasures in WWM almost daily! -Graham T.> Glenn Nightlight And Photo Period  9/18/06 Crew- I have a 54 gallon corner bowfront tank that houses a pair of clown's and their BTA as well as a number of SPS, LPS, and polyps. I understand their is mild disapproval for keeping a 'mixed' tank, but we know BTA's are one of the more stationary anemones around. <News to me.  If any anemone is in an area not to their liking, they will move.  Just changing direction of the water flow can cause them to move.> This tank also houses a number of gobies, and I woke up one morning to find one of them dead on the floor. This is not the first time this has happened. Covering the tank is not an option because of halide lighting which requires a cooling fan. <Do not understand...Is this lighting mounted in a hood?  If so, I see no reason not to cover the tank with a piece of acrylic/glass.> I took a look in the middle of the night a few days back and confirmed that the clowns are bullying many of the small gobies. I added a standard fluorescent 18" 20W fully actinic bulb in an effort to keep fishes from leaping out in terror. Will this type of bulb at this strength negatively impact the photoperiod of my tank with respect to my corals and/or anemone?  I am concerned that this amount of light might create 24 hours of 'day' with 0 hours of 'night.' Is this a possibility? <The macro, if any, and the coralline do enjoy a resting period, something the actinic is not going to provide.  Try using a couple of LED "Moonlights". Foster & Smith sell these under the name "Lunar Lights", and can be had for about 15 bucks each, in your choice of colors.> Thanks <You're welcome.  James (Salty Dog)> Cj

Moon Lights - 01/24/2006 Dear Crew, <Hi Jimmy.> I wish to thank you all for your help. <We are glad to give it and you're quite welcome.> I have MoonLites on my 180g FOWLR.  When the MoonLites come on at night, my shrimp, snails and hermits become more active. I have noted that while some fish seem to bed down others seem to roam around. I have experimented, and have noted that if I drop a food pellet into the tank, my emperor angel will actually feed, though more sluggishly when compared to the daytime. I have done some diving in previous years and the illumination is similar to a full moonlit night on a shallow reef. In my tank the fish are definitively more active at night when the MoonLites are on. When I walk by the tank with the MoonLites on the fish do not seem to spook as easily. I do not see any signs of stress and the tank is a sight to behold. I like the MoonLites because I can observe the tank at night. Am I doing any harm with the MoonLites ? <Good observations. I've noticed much of the same in my tank. These lights aren't going to cause any harm, so just enjoy.> Thanks Jimmy <Welcome. - Josh> Nautilus and the Moon  9/21/05 Hello Bob, <Doug> Would you please take a moment to answer the following? <Sure> On your snail site, a Sean MacKirdy mentioned that he installed a "moon simulator" on his snail tank. He felt that the spawning of a hundred plus creatures was the result of "the full moon" simulation. <Lighting, changes are amongst the more powerful "triggers"...> Please let me know, very briefly, how a "moon simulator" works. <Mmm, an alternating light source, more bluish... lower intensity... some folks even arrange for this to wax/wane with time at night...> More importantly, are you familiar with the theory that the Nautilus Mollusk creates one spiral chamber per day and after 30 days-- following the moon's cycle-- abandons the shell and begins to build a new one? <Mmm, no... what does it do in the "meantime?" when it has no exoskeleton?> I greatly appreciate any word you can send.                                        Best: Doug Flaherty                                                 University of Wisconsin <Be chatting, Bob Fenner>

Become a Sponsor Features:
Daily FAQs FW Daily FAQs SW Pix of the Day FW Pix of the Day New On WWM
Helpful Links Hobbyist Forum Calendars Admin Index Cover Images
Featured Sponsors: