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Extremely shy O. briareus


Apr 29, 2021
I received an O. briareus December 9th. He inhabited the same cave for a long time but I haven't seen him at all in three weeks and its beginning to make me anxious. The cave does have a back door.

I know I've made at least one big mistake: the acclimation process was too bright because I was excited and wanted to see him. After giving him a week of darkness then decreasing the light hours/brighteness I would still periodically shine a light to find him.

I know I have made those mistakes. I also think I made some other ones.

I had a ton of crabs, amphipods, snails and shrimp so he still has a lot to hunt in there. I find shells and next to no crabs. Could be he's got so much food there's no reason to not hide from the huge animal shining lights trying to find him. There's still at least 15 snails and two crabs plus an amphipod population nurtured for almost a year.

There was a small gap in the lid for awhile that allowed an escape but security camera footage didn't pick it up and I have yet to find a mess on the floor or smell something. The gap was by the highest flow area of the tank.

There are 5 peppermint shrimp that might be bothering him with their movements. When I first acclimated the octopus the shrimp were definitely annoying him and he pushed them away but made no attempt to strike.

The security camera picks up the shrimp but not the octopus on the rocks. The only time I can see him is when he is off of them.

When aquascaping I did give him a little courtyard out of sight in case he needed more privacy. Thought it would be an occasional thing but he does have a place to go where I can't see him.

I spend all my time at home either watching the tank or the tv next to the tank. I have never seen a large cluster of detritivores that would devour a corpse. It's a studio apartment and the tank is 10 feet from my bed and three feet away from the chair where I spend my recreational time.

If anyone could offer any advice I would deeply appreciate it.
Have you seen signs of the octopus eating in the past 3 weeks? That is a good indicator if they are still in the tank or not. Have you ever seen any empty snail or crab shells in the tank?

I'd recommend removing the shrimp if you are able, especially if the octopus hasn't shown interest in eating them. The snails can stay because they wont bother the octopus. How big are the crabs in relationship to the octopus? Do they live long in the tank or get killed and eaten quickly?

If your security camera has IR light then you could film the tank at night and see if you can see your octopus moving around, I don't know if briareus is nocturnal or not.

It could also be that your octopus is female and is preparing a den to lay eggs.

Really you wont be able to know for sure unless you find pieces of discarded crab shells or go rooting around in the aquarium to try and find them.
There are shells accumulating and they are typically found in the area out of sight where I think he might be. There was one large crab about the same size as the octopus but that one was vanquished, the rest are small. The crabs came in with my 45+ pounds of KP aquatics uncured live rock.

The camera does have IR but the octopus is so good at blending in it's a rare chance it's picked him up.

Might go rooting around today. Not easy with tall aquascaping. I regret buying the shrimp but there are so many caves I don't have much hope catching them.

Hope she's not laying eggs, only received in December.

Also I had a ton of Macroalgae in there for awhile for extra cover but the snails have almost finished it off.
O. briareus Is nocturnal. This species can be - but isn’t always - very shy. your best bet is to leave your octopus alone for a while. Don’t go “rooting around”. Remove the shrimp. Hopefully your octopus will come out in the open a bit more. If you practice, you will develop “octopus eyes”, the ability to spot a well-camouflaged octopus.

Last Wednesday I gave the sand a vacuum, bumping my rock and had to reassemble some of it. I took the opportunity to examine each rock I had to replace and there was no trace. Began to really despair. I got him December 9th and he mostly stayed put in a visible cave. Left that cave New Years eve and disappeared since. I left the lid ajar for one of those weeks and feared the worst.

At last while looking though caves with a light I noticed something change color and move fluidly and at last was able to relax. Now if I stare long enough at this cave after the lights go out I'll get to see an arm or two poke out. The IR overnight camera indicates he stays put basically all night. There are still a few surviving crabs, hermits, and 20+ turbo snails. Amphipods galore.

I've stopped shining lights and ordered something to trap the shrimp that'll arrive in a week. No chance at catching them with a net. Haven't seen them close to one another since acclimation day.

Is there anything else I can do? Thinking about offering a small fiddler by hand but it looks like I just need patience.


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