• TONMOCON VII Announced | MBL at Woods Hole | Apr 6-8, 2018
  • Thanks for visiting! TONMO is the world's greatest online cephalopod enthusiast community, with interactive content going back to May of 2000, and a biennial conference. If you'd like to join in on the fun, become a TONMO member -- it's easy and free. You can follow us on Facebook and Twitter for more cephy goodness.



Aug 24, 2009
i plan on getting an O. Mercatoris and i've read there knockternal. i was told that if you use red lighting they will come out and i have only seen pictures of them as pets with red light. the sites that i am ordering my stuff from all have blue lights but not red ones. will blue lights work just as well or will i have to find other websites?
also (these is kind of unrelated) i can't seem find a site that sells livestock as food (in my case ghost shrimp and fiddler crabs). is their a site you know of that sells them.


Staff member
Sep 4, 2006
Gainesville, GA
This is my experience with night lighting. It does not answer your question about blue lighting but I will mention what I have tried with red:

I have raised 1 WC (Trapper), one generation of captive born (Trapper's Young) and one generation of captive bred(Trapper's grandchildren, inbred with sibbling) so all my successful experience with the mercs have been only one genetic line. I used two tanks and both had red lights 24/7. The larger tank had dim daylight lighting in a relatively dark room. The smaller tank had no extra tank lighting but was in a room with full daylight ambient from either the room lights or the outside lighting. Having never tried blue, I can't speak to how well it would work but all of mine accepted the red as night and I could easily watch them after dark.

All three of my briareus notice(d) and dislike(d) red flashlights but I don't know if a constant red light would also be bothersome. Unfortunately, our red nightlight that I had for one of the tanks has died so I have not been able to try it.

I also used a red nightlight on one of our hummelincki (diurnal) tanks successfully (nothing like watching an octo sleep - kind of like watching paint dry :wink:). When the power would go off it would reset to white light and THAT bothered him and he would pace the tank at night. After several power outages, we removed the light.

Members online

No members online now.