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Need some help!!!


Oct 16, 2007
I was turning off Rigby's light tonight and I noticed he is missing 1 of his legs. It is 90% missing.... He shares a tank with 2 damels (later food) and some medium hermits that he snacks on and a bunch of mushrooms... There are some LARGE bristle worms in his tank and lots of other bristle worms... He has a magnum 350 filter (no parts to hurt him) and an octopus skimmer ( the pump is in an acrylic box with holes drilled into it...

what happened to his arm and what do i do?
none of his other arms look damaged

doing a water change tomorrow, but no ammonia, and trace nitrates...

my only guesses:
he did it to himself but why?
he got bristled and he did it?
one of the hermits did it?
the damsel?
stuck his arm in the hole to the box to the pump (don't think it would take that much off of his arm)

anyone think one of these is possible or likely?

any help would be great... I don't want him hurt...

We've had cases where a small octopus loses a leg to a larger crab (and doesn't succeed in killing it). Just how large is Rigby and how large are the crabs? Are they a size he is able to kill? A week ago you were killling crabs for him.

I've never kept damsels - I know they can be aggressive and we don't recommend keeping them with octopuses, but whether they might bite off a leg?
Perhaps someone else can respond herer.

The safest tank for your octopus is one where there are no larger fish or crabs, they're smaller than he is. Snails can be larger because they're not a threat.
The roles of predator and prey can be reversed, depending on size.

Watch him carefully, hopefully this won't happen again.

The good news is octopuses can regenerate their limbs. I had one I bought that I named Gimpy as he was almost totally missing a leg. Within about 2 months the leg had grown back and I could hardly tell which had been missing. I would also remove the larger hermits and the damsels if you can.
The hermits are not too big for him but he is "special"... he can't kill fiddlers.... he does kill hermits... but not as often as he used to...

His mantle is now 1 1/2 inches probably and his legs seem so long... but they are probably about 2 1/2 inches long

I don't want to take out all of the hermits... I want him to have something to snack on... but if I take out the medium sized hermits and put in some tiny blue legs is that enough for him to snack on?

I guess I can take out the damels... they are little too... but I just thought he might want to hunt them and snack on them... but it doesn't matter to me i guess...

oh and he has 2 small turbo snails.... but they wouldn't cause any problems... they live mostly on the lid... lol... i think they know what is down there...
I wouldn't worry about the hermits, they are mostly scavengers. Other kinds of crabs could hurt him, though. I would get rid of the damsels (good luck catching them without removing all of the rock...), they can be aggressive and territorial.
one damsel is but the other has been held up in the corner...

but i don't think the damsel could take off a leg????
I took my water down to the LFS and everything checked out fine... but my yumas in the tank are mad and i just don't know what is going on...
the most common problem we've heard about with damsels is that they'll zip in an nip at the octo's eyes... If it were the nasty form of autophagy, the octo would typically bite off several of its arms. I have wondered if autophagy is an out-of-control reflex of a natural behavior octos have to sever one arm if it's somehow problematic, though; so maybe there was an infected injury on that arm and the octo severed it so it wouldn't spread, or somehow the arm got caught in or under something, and it decided to lose the arm rather than stay trapped.

This is probably a sign of my tank-keeping ignorance, but what are "yumas"? I'm glad you got your water checked and it was OK... is the temp OK? That's one thing that wouldn't show up at the LFS.
Animal Mother;106603 said:
Yumas are Ricordia mushrooms.

oh, ok. thanks. how do you tell if a mushroom is mad? Color change? Posture?
Most of them don't do anything, and if they do react, they shrink. There are some larger carnivorous mushrooms that slowly curl up into a spere around their prey. Seriously doubt one could catch and contain an octopus.
Animal Mother;106611 said:
Most of them don't do anything, and if they do react, they shrink. There are some larger carnivorous mushrooms that slowly curl up into a spere around their prey. Seriously doubt one could catch and contain an octopus.

I guess I was inferring SandV meant by "mad" something like "looks like they're reacting to the water quality somehow" as opposed to "got mad and chomped the arm off the octo." But I'm not sure what, if anything, that may have to do with the missing arm.

SandV, can you give more details on what you've observed, what you've measured, and what the LFS tested for? Numbers might be helpful... I'm mostly asking since I know there are a lot of experienced tank-keepers who might be able to make a quick diagnosis; I'm just a neophyte at this stuff, but I've read enough of these sorts of threads to know that the more specific info the real experts see, the more likely that they'll pinpoint particular issues rather than shrugging and saying it could be a number of different things...
temp is normal
0 nitrites
trace nitrates
.5 phosphates
0 ammonia
pH 8.0
sq 1.020
I even tested for copper- 0

Monty - the mushrooms are closed... not open fully like they would be if they were happy...

but I have probably 200 mushrooms in the tank, red, tonga blue, watermelon (green stripe), and yumas (ricordias) and all of them are normal exept the 30 or so yumas... so I would think it is something to do with the water quality... but I am out of ideas...

None of the mushrooms could hurt him... i am sure of that... the largest is probably 3 or 3 1/2 inch yuma but they are not known for eating fish... and definately not strong enough to take an octo's arm...

He isn't out right now but i want to take some more pics of him and see if anyone thinks he isn't a baby bimac...
I took out all the hermits and am working on the fish....

I do not have any saltwater mixed... i thought shane started it this morning

Do i just mix some water now and do a water change???

He did not come out for dinner and did not come out to check out what I was doing???

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