[Octopus]: O. Briareus - Unwitting Ichthyologist at the Florida Museum

Mar 12, 2020
Gainesville, FL
Hi everybody, happy to finally be posting on this site!

My name is Gabe Somarriba and I'm a technician working in the Florida Museum's Ichthyology Collections. While I've kept many fishes both marine and freshwater, I was never able to keep a cephalopod until recently. You see we have a big 90 gallon marine aquarium in the lobby of our collections building stocked with some brittle stars, hermit crabs, sea cucumbers, urchins, a big ol slipper lobster, and until recently soapfish, toadfish, and a sergeant major; the soapfish nuked the tank with their toxic mucus and killed off themselves and the other fish. For a while it was an invert paradise and I figured I'd take the opportunity to go down to South Florida, visit my parents, and get some neat little blennies, gobies, and damselfish for the tank. What ended up happening is on my way down Friday night I stopped along the beach north of West Palm and searched among the partially submerged rocks with my headlamp. I saw what looked like a big, turquoise soft coral on a rock but, upon touching it and getting touched back, turned out to be a big beautiful Octopus briareus! I ended up finding 5 in total that night (two of which appeared to be spawning) and netted the smallest one for the museum's tank. I came away with a grand haul of one octopus, a heavily armored Calappa flammea crab, an urchin, and 2 nudibranchs.

The octopus survived transit in a bucket with an aerator and even ate a crayfish. I ended up putting it, the urchin, and the Calappa in the tank. She inked and immediately hid in a big pile of rocks, not coming out again until later that evening. It has now been 3 days and nobody has seen her (the aquarium is in a high traffic location and everyone in the museum is very excited about it, especially the IT department because the aquarium is right outside their door). At one point we thought it might have escaped, but the next morning we found the slipper lobster picking over the empty remains of the Calappa that I had so naively thought would be safe from a hungry octopus. The entire tank is fed daily with frozen scallops and shrimp, but I worry she may not be getting enough. I was thinking about putting a crayfish in some kind of container for her, thoughts? Really I'm just a little anxious but the information on this site has helped a great deal! We hope to see her soon!

Bonus Crustacean Friends pic included!

Its not surprising that a new octopus won't eat for a few days upon its initial arrival. Remember that they can go multiple days in the wild without eating, so I wouldn't be concerned yet. Your animal may be hiding because of all its other tank-mates. Octos are most often solitary creatures and can be discouraged from eating/moving about the tank if they have tank-mates that are picking and poking at them.

Some strategies to try: you could spear the piece of shrimp onto a stick (a long zip tie works well for me) and offer that to the octopus by gently rubbing the piece of shrimp along the suckers on one of their arms. Alternatively, you could try to add a fiddler crab (I feed local Florida fiddlers to my bimacs) and see if the animal is interested in eating that.

Again, I wouldn't worry about them not eating for a few days or not eating every day. If they killed and ate the Calappa then they may not be interested in eating for the next couple days.
O. Briareus should easily take to BEING FED thawed frozen shrimp (but not dead shrimp in the tank). You can try to stick feed any seafood starting with a piece about the size of its eye then building up to sizes being rejected or not fully eaten. If a particular food is rejected, try again in a week or so -- I usually try three or four times before giving up but shrimp has always been a main food for my animals. If you can get blue crab claws -- avoid feeding the whole crab -- they can be frozen and are also almost a sure bet (crack the outer shell before offering. Be sure to offer food at the same time every day. They are crepuscular animals (early evening and early morning foragers) by nature but can be trained to come out for a short time and be a little bit social if you feed a bit earlier than sunset.

Live fiddler crabs are also ideal but ANY small crab is great. Mine always ignored hermits but others have had younger animals eat them. You can use live crayfish (just release them to the tank, they will live for a short time) if you remove them if they die before being eaten. I am afraid you lobster is next on the menu though.

I strongly recommend NOT putting any fish in the tank -- for both the fish and the octopus health.
Awesome thank you so much guys!! I'll definitely try enticing her with little bits of food, as of right now I just don't see her but as soon as I see a tentacle I'll give it a shot. Glad to hear they can fast for a bit, I was under the impression that they had a high metabolism and needed to constantly eat. What is a normal feeding regime for an adult O. briareus? I think the local asian market occasionally has live blue crabs, I could freeze those in preparation. @DWhatley as a matter of fact a division is forming between those who side with the slipper lobster and those who side with the octopus; we may have to hold a vote and find out which one has to be rehomed!

Please feel free to move this thread over, I'll post updates as things happen in the tank!
If you get your blue claws from a market, see if you can get only the claws. I go to our local Asian market when they have them and take only the loose claws from the bin (give them a good smell when you get home and then again when you thaw them). Be sure you explain your intent though, I had one clerk (who spoke no English so it was hard to explain, especially because he was mad at me "ruining" the crabs that were for sale) become almost violent with his distaste. You cannot freeze the whole crab (the innards will poison the meat) so cook the body and freeze the claws if you get them whole or dig out the meat immediately after killing them. For larger animals the whole crab will be conquered but leave a really bad mess in the tank.

I suspect you will not have a rehoming choice, maybe even before you read this. Tonight's hunt is likely to include slipper lobster.

One thing you may want to try once the octopus is a little larger is live shrimp (your local bait shop likely has some -- I have transported bait shrimp back to GA in the past). Only put one or two in at a time as they don't survive long (a week or two) in a fish tank but will give hunting stimulus for the octo. SueNami did eventually catch the shrimp in the video below.

Any name yet?

I just noticed the open clam shell in the tank. I typically keep live clams in my tanks for filtration. If you source them from a market, keep them overnight in a bucket of tank water to allow them to purge their existing water and waste. Be sure to put a top (not air tight) over the bucket or the purged water will be everywhere and the clams will die from lack of water. Sometimes they live for years, sometimes the octos decide they are the perfect snack. For your little one, open a live clam (I don't recommend oysters -- again for concerns with mucking up the tank but they are fine for the octo) and place it near her den. If it is uneaten the next morning, remove and try another time. Clams don't seem to foul the water detestably.
Wow, thank you for all the great advice! The clam shells in the tank are food for the slipper lobster; she just grabs em and seemingly applies pressure with the points of her feet until the shell cracks. We did try to put a clam by the octopus den and see whether she'd eat it, but the slipper lobster sniffed it out and ate it. Here's a photo of the entire setup:


I've been checking up on her daily and there have only been 2 real developments:

On Friday I noticed that she had grabbed the empty Calappa carapace and a clam shell and pulled them up against a rock, so now I suppose we know where she's holed up.


Also on Friday, my buddy Jacob cleaned out the tank (he owns an aquarium maintenance business and has a contract to service several of the university's tanks) and removed all the shells in addition to moving some of the rocks. He knew the octopus was in there and was probably just trying to tidy up, but I wish he'd left the calappa shell as a testament to her power.

On Sunday, I found the legs and claw of one of the hermit crabs on top of the rock she had holed up under. She had also replaced a clam shell at what I guess would be the entrance to her lair.



Otherwise everything is still the same; I'm gonna put in a crayfish after work and stop by the asian market to get the crabs. If they don't have crabs I'll probably just get some fiddlers from the pet store.

Trying to figure out what can be done with the slipper lobster, might have to ask Jacob to put her up in one of his tanks in the meantime.

Still no name yet! We were thinking of giving her and the slipper lobster little old lady names like Barbara and Ethel.
New development! Our octopus has shed her suckers! Jacob told me there were some polyp looking things floating around the tank, so I go up, collect a few, and look at em under the scope.


They reminded me of this image from the FAO guide to marine resources of the Western Central Atlantic:


And a quick google search confirmed that octopuses do indeed shed their tentacles! This whole experience has been so fantastically interesting for someone unacquainted with the ways of cephalopods!
LOL, Octopuses don't have tentacles. Decapods (squid and cuttlefish) have 2. All have 8 arms. None of them shed their arms but can regenerate them if they are removed by a predator -- a few can actually break off an arm to allow them to flee like a lizard with its tail. All of them do shed the lining of their suckers and that is what you are looking at in the microscope.
Hi everyone, sorry for the long break but all of us at the museum were kind of scrambling to adjust to the new covid regulations. Anyhow, yesterday I saw that our lovely octopus Blue (that's the name we finally decided on) has eggs!!


They're maybe around 1 cm in length and milky white. Since my last post she had remained quite shy, although she would venture to put out a tentacle and snatch food during the regular feedings in the morning. She would get more rambunctious with whole crabs and shrimp; we even put in a school of silversides and a whole slew of spider crabs for her to hunt, which she finished in short order. Thankfully she still has not touched the big slipper lobster, brittle stars, or sea urchins. It wasn't until maybe a week ago that she stopped coming out for feedings, so at the end of last week we moved some rocks and found her with her clutch. We'll wait and see whether or not they are fertile, but if they are we may have some folks around the museum who would be interested in attempting to rear these little buggers. I'll try to keep updating you all on their progress!
It is quite likely that they are fertile. I took a series of images over time and made a collage with Kooah's brood that may be helpful as you watch the eggs.

@Neogonodactylus recently posted a photo of a blue ring and her clutch that show just about every stage of development all in one cluster. This is an amazing image. Not only do you see the eyes but a couple of animals are developed enough to see their chromataphores. Some of the octos show the yolk sack toward the narrow end where others have flipped and it is toward the wider end.

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