Lighting For Octopus?

[andrewey]

I've read most of the articles I can get my hands on, but maybe someone can give me a concrete answer. I have a pgymy octopus right now, and I'm trying to find out what lighting would be best. Right now I have a 18w blue actinic pc bulb over him which produces a dull/somewaht dark light, but enough that he hides out most of the time. It switches off every 12 hours and then the party begins!

So my question goes like this: What would be the best lighting scheme for the octo (forget my viewing pleasure). Does he need light to set his nocturnal behavior or could I leave the tank dark most of the time?

 

[Joe-Ceph]

Octopus eyes see blue light better than we do, but not red light. As a result, light that is weighted toward the blue side of the spectrum (like actinic?) will seem brighter to them than it does to us, while redish light will seem dimmer to them. Nocturnal species aren't likely to come out with any light on that doesn't seem dim to them, so I think most people use a red light (in a dark room, at night) to view these species, because the octopus thinks it's dark, but we can still see a little. During the day a nocturnal octopus will probably hide from any visible light, so use whatever works for you, and the rest of your tank, during the day, because you probably won't see your octopus anyway, although actinic might seem extra intense to them. I don't like cleaning algae so even though I have a diurnal species (bimac) I just use ambient light during the day (in my living room) and a regular 10K fluorescent tube when I'm home in the evenings, for viewing (like you might use on a fish-only fresh water tank.)

 

[andrewey]

Thanks for the response!

If I took it to the extreme, would it be ok, if I didn't use any light at all during the day, and just relied on whatever ambient light existed (its dark/low light, but contains ambient light via a window)? I have red leds rigged up for night viewing, but I wanted to know if it would be too dark at times and mess with his "cycle"

 

[DWhatley]

With my merc tanks, I left the red light on 24/7. One tank had low (LED) daylighting the other only ambient with morning facing, uncovered windows. With my briareus, I leave a portion of the tank lit with red light 24/7 and actinic/white 50/50 lower wattage compacts during the day (both for viewing and the few corals I keep in the tanks). There does not seem to be a need for anything but ambient daylight so the additional light is optional. If the room is totally dark during the day (no ambient), you might want to experiment with setting a night day cycle using the overhead or lamp lights to encourage activity best suited to your enjoyment.