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Moonlights for octo tank.

Oct 31, 2003
OK, Has anyone done this or studied it? I have a large reef tank with moonlights and the corals, shrimp etc, Seem to really thrive under it.
So I decided to to put some in the octo's tank, They have been in for about a week and he really seem's to like them. He comes out more and hunts/forages around the tank at night for clam's, amp's etc. But the thing I've noticed the most is he is very active during the day now, As where before the lights he would hide all day and not really even move around much at night.

Just my observation......Or Maybe he is just getting more comfortable with his surroundings.

The lights by the way are a 475nm led (the same wavelength as natural moonlight) Total cost for the reef and octo tank was less than 20 dollars..... :biggrin2:
Hi Octopus Reef,

This is interesting. Maybe your octo feels more secure with some light at night.

Who makes these moonlights? Are they available at most LFSs or online?


My cuttlefish tank was ran by a light unit called Ufo Complet (no e, its german) and it has 2 x 150watt MH lights, 2 x 30watt fluros and 2 100watt halogens that were night lights, they get brighter up to full moon and dim again over the rest of the month. An inbuilt computer regulates all the cycles...


Anyway, yes it makes a huge difference. the cuttlefish would always go into full breeding display at full moon and the days either side... The moon is the best trigger for spawning.

nancy, most shops will sell moon bulbs, they are just like the dark blue actinics. might be a good way of watching a nocturnal octo
I just made mine, I have had some store bought ones but they we're to bright and the fish seemed "restless", the system I made is just the right amount of light you can't even tell it is on unless all the lights in the house are off. If you buy some, make sure they are the same nm as natural moonlight (468 to 475 or so) or you will drive your octo crazy. The best part about making them (other than the cost is about a 100-200 dollars cheaper than most store bought units) Is that you can adjust them to fit your tank as they dont require a "housing" they are very small requiring no hood mod's. Here is a couple pic's. One of the reef and one of the octo tank.
Cold Cathode Set-up

I used two blue cold-cathode tubes (sold for use in computers, actually) for my moonlighting. I am using two 12" blue tubes.
Currently the "moonlighting" come on 1.5 hours before my main lights and stays on about five hours after the mains go off, leaving about six hours of darkness.
This does not recreate the moon so much as dusk and dawn period. I mainly set it up because it was pretty cheap (about $40 in parts) and I work nights, so I wanted to be able to appreciate the tank when I got home from work at 1am (the moonlighting goes off at 2am).

A picture:
The parts are simple things you can get at a electronics supply store ( or radio shack here in the states) You need some blue LED's (make sure they are 468 to 475 nm) How many ever you want ( 2 is plenty for a 30 gallon tank 4 for a 55 gallon). Then you need a resistor for each light, mine were about 150 ohm and a 6 volt power converter. I just soldered a resistor to each positve (long) side of the LED and hooked everything together with speaker wire. It is very easy to tell positive and negative if you use speaker wire, and seeing as how it is only 6 volts speaker wire is more than enough. Here is a link to an artice about doing this very setup (but in my opinon his are much to bright for to simulate moonlight). I hope this helps.http://www.kaotica.com/frag/diy/moonlight/
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