Lighting Nocturnals | The Octopus News Magazine Online
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Lighting Nocturnals


Larger Pacific Striped Octopus
Staff member
Jul 13, 2008
Livonia, MI
I have some questions about lighting for nocturnal octos. I've read the merc threads, and I know D does red lights 27-7 (is that right?). Are the lighting needs the same for all n'octos? "Thing 2" (IDs right now are macropus or boki :hmm:) in the 55 gal. is nocturnal for sure, and absolutely NOT a merc, should I do red lights 24-7 there too, or just at night? Why would it care about lights during the day if it is sleeping? The merc peeks out at me all day from it's den, so I can see keeping lights on for it in the day if it is awake. "Thing 2" sleeps under a rock all day.

Also, does it make a difference if the lights are regular actinic aquarium lights filtered through vellum, or are red LEDs better? My husband brought this up to me, it may be he'd like an excuse to visit the hardware store, but who wouldn't?


TONMO Supporter
Staff member
Mar 8, 2004
I've tried to research the spectrum of red LEDs, and found that they vary somewhat. Now that I've got the spectrum of vulgaris rhodopsin, I've been meaning to put curves together, and see whether red LEDs tend to have much overlap with what an octopus sees (assuming most octos have similar perception to vulgaris). In practice, people seem to have had better luck with the vellum, but some people have used red LED flashlights. I've wondered if red laser diodes without the lens would be good, too, but haven't found a good source for them. If you try it, I'll be very interested in the results, although LEDs add up pretty fast. If you do try LEDs, please keep track of the brand and what wavelength they say is "peak"-- usually it's around 650nm, with longer values getting more red until they're in the infra-red, and shorter ones getting more yellow, green and blue. You'll want ones that are more reddish and less orange. I think some "bright red" LEDs are doped with something that spreads their spectrum to include some yellows, so I'd stick with "regular red" instead of "bright red" but I'm not certain of that.


Staff member
Sep 4, 2006
Gainesville, GA
I keep the red light on 24/7 for several reasons. At night, I don't want a "darker" period of time than when I am viewing them. Even though they don't see red, I am not sure that the lighting makes the tank completely dark. I am sure that the red light is "dark" enough for them to be comfortable with and they will hunt and eat. I keep it on during the day so that the "dark" is consistent (this may make no difference at all). The tanks do get regular ambient light and Greg does give his tank day lighting to facilitate other things in the aquarium.

I have seen the mercs react to a red LED flashlight so I would say they detect something with the LED's. In my velum red tank, I had better viewing and more active octos than in the LED lit aquarium. The aquariums could not be more different so the lighting may not be the reason.

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