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octopi

Contents:

  1. Octopus
    by fester/island.COM (Mike Fester) (Mon, 23 Mar 1992)
  2. Octopus
    by cigliano/bu-bio.bu.edu (John Cigliano) (2 Sep 92)
  3. cuttlefish
    by cigliano/bu-bio.bu.edu (John Cigliano) (4 Sep 92)
  4. (M) My fish squirts me to be fed?
    by malloy/lyra.scg.hac.com (Jerry Malloy x3337) (9 Sep 93)
  5. [M] Octopi
    by gseven/lacerta.unm.edu (Roy "Gary Seven" Corey) (12 Oct 1993)
  6. [M] Octopi
    by laurence/cco.caltech.edu (Dustin Lee Laurence) (19 Oct 1993)
  7. >[M] Octopus, Squid and Cuttlefish
    by lucas/ucsu.Colorado.EDU (Michael A. Lucas) (Fri, 15 Oct 1993)
  8. >[M] Octopus, Squid and Cuttlefish
    by laurence/cco.caltech.edu (Dustin Lee Laurence) (19 Oct 1993)
  9. Blue-ringed octopus
    by mvp/netcom.com (Mike Van Pelt) (Tue, 16 Mar 1993)
  10. Blue-ringed octopus (WARNING!!!!)
    by andrewt/cse.unsw.edu.au (Andrew Taylor) (Wed, 24 Mar 1993)
  11. Octopus in 5gal?!?!
    by mrb/oregon.uoregon.edu (Michael Robert Beale) (20 Apr 1994)

Octopus

by fester/island.COM (Mike Fester)
Date: Mon, 23 Mar 1992
Newsgroup: rec.aquaria,alt.aquaria

In article <1992Mar20.234046.13878-at-unlv.edu> robert-at-unlv.edu (Robert Cray) writes:
>I'm thinking about getting an octopus.  I'm told by a friend that they
>need to be kept in a refrigerated tank, otherwise they will become sick
>and die after about 6 months.  The local fish store has one that is not in
>a refrigerated tank and claim it is unecessary.  Anyone know the real scoop?
>Also what are they likely to get along with and how fast do they grow?
>
>					--robert
>--
Depends on what kind of octopus, of course. Cold-water types need to be kept in 
cold water :-) My experience with them has been good. I kept mine with a
panther grouper, a volitans lion, and a powder-blue ribbon eel. You should have
seen the action when I dropped the feeders in! So, kept with other carnivorous
fish of roughly the same size, everyone got along fine.

The octopus would actually crawl onto my hand after a while (DON'T TRY THIS 
WITH THE BLUE-RINGED VARIETY), but of course you have to keep your hand away
from the volitans.

In general, they do very well. Keep crustaceans out of the tank (octopi think
of them as french-fries) and keep triggers out of the tank (they'll nip the
tentacles, or so I'm told). Keep a TIGHT lid on the tank. 
Mike
-- 
Disclaimer 
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Octopus

by cigliano/bu-bio.bu.edu (John Cigliano)
Date: 2 Sep 92
Newsgroup: rec.aquaria

>In article <cburns-020992133506-at-end.chem.indiana.edu> cburns-at-ucs.indiana.edu (Chris Burns) writes:
>In article <1992Sep2.123028.5300-at-echo.philips.nl>, johanb-at-echo.philips.nl
>(Johan Slob) wrote:
>> 
>> 
>> Does anyone know anything about keeping an octopus in an 
>> aquarium?
>> 
>>   - size, temperature of aquarium
>>   - best sort of Octopus
>>   - recommended literature
>> 
>
>
>I've heard that they're very hard to keep.  Mostly because it's very
>difficult to keep them in the tanks.  No hole is too small, no cover too
>tight for them to get a tentacle in.  Getting them to eat (assuming it's
>still in the tank) is also supposed to be troublesome.  I've also heard
>that even some of the big Aquariums have troubles with octopuses.  There
>may be some species that are more suited for aquaria then others, I don't
>know about any of this though.
>
>Good Luck
>
>Chris

Octopuses are indeed difficult but not impossible to maintain. I have had
limited success maintaining octopuses in aquaria (my doctoral dissertation
is on octopus behavior and ecology). You must be aware of several facts
before deciding on whether to keep octopuses: (1) they do get out of aquaria
very easily. An octopus can get out a hole 1/4 the width of its mantle since
the only hard part is cartilage surrounding its brain - if it can get an arm
through the rest will follow. (2) they are voracious eaters and usually will
only eat live food. Crustaceans are their favorite but will eat fish and 
snails to a lesser extent (but they will not eat fish or snails exclusively).
Some species will eat mussels and clams. Be prepared for a major food expense
(unless you can collect the food yourself. (3) octopuses are very sensitive
to water quality changes and (4) they are semelparous, ie., spawn once then
die, and very short live. The species that can be kept in the average sized 
aquarium will live between 6 mos. to a year and (5) octopuses are nocturnal
(active at night) and tend to hide in their dens when not active (which is
about 70% of the time) so you would not see much of your octopus. Also, 
octopuses ink when startled or threatened and a medium sized species will
ink enough where you might need to do a water change.

With that said, I do encourage you to try to keep an octopus (don't try
to keep more than one in a tank since they will fight) if you don't mind
a challenge. They are extraordinary animals. I reccommend keeping the
Atlantic dwarf octopus (_Octopus joubini_) since it is small (they hide in
clam and whelk shells). I found that they relish fiddler crabs (about one a
day). You can purchase them from the Gulf Specimen Marine Laboratories, Inc.
(904) 984-5297. _O. bimaculoides_ (the mudflat octopus) is somewhat larger
and lives about twice as long (6 mos for O. joubini, 1 - 1.5 years for O.
bimaculoides). However, the only source that I know of is a collector from
S. Cal. Pet stores sometimes will have octopuses for sale. 

I hope I was of help.

John A. Cigliano

References on keeping octopuses:

Hanlon, R.T. & Forsythe, J.W. Advances in the laboratory culture of octopuses
for biomedical research. Laboratory Animal Science, 35(1):33-40.

Forsythe, J.W. & Hanlon, R.T. 1980. A closed marine culture system for 
_Octopus joubini_ and other large egged benthic octopods. Laboratory Animals,
14:137-142.


cuttlefish

by cigliano/bu-bio.bu.edu (John Cigliano)
Date: 4 Sep 92
Newsgroup: rec.aquaria

In article <1992Sep4.175300.888-at-cco.caltech.edu> laurence-at-cco.caltech.edu (Dustin Lee Laurence) writes:
>cigliano-at-bu-bio.bu.edu (John Cigliano) writes:
>
>[Cuttlefish]
>
>>However, they are champions when it comes to inking. I've seen _Sepia
>>officinalis_ (the common cuttlefish found in the mediterraneum and eastern
>>atlantic) project ink out of its tank and hit a wall over 10 m away. 
>>The amount of ink is enough to turn water in the largest tanks black. You
>>would need a heavy duty protein skimmer and a very good filtration system
>>to remove the ink.
>
>This brings up an interesting question: how harmful is cuttlefish and/or
>octopus ink?  I've heard that it is quite poisonous, and I've also heard
>that it's only harmful in that it tends to suffocate the critter if not
>removed.  Is it species-dependent?  Any idea on how long one has to remove
>the stuff before serious harm is done?
>
>-- 
>Dustin Laurence       "As sensitive and broad-minded humans, we must never
>                       allow ourselves to be in any way judgmental of the
>laurence-at-alice         religious practices of other people, even when these
>caltech.edu           people clearly are raving space loons." -- Dave Barry

Cephalopod ink is not poisonous. In fact, in Spain and Italy (and probably
other countries that I am unaware of) cook cephs in their own ink (give it
a try if you have the chance - its really very delicious). The danger is 
that it could suffocate the critters in the tank. Ink is a combination of 
protein and mucous which is why it affects respiration. Its my experience 
that if an octopus inks one or two times it isn't enough to be dangerous 
(octos don't ink in large amounts like the cuttlefish). However, repeated
inking by an octo, which happens if itd really spooked or harassed, or a
single inking by a cuttlefish could be dangerous. Basically my rule of thumb
is that if inking causes the water to turn grey but I can still see the 
critters, I don't worry about it. A cuttlefish will turn the water completey
black, which will cause harm. If you catch the inking early you can remove
much of it with a fine mesh net since the ink is part mucous. Animals are
affected if they are exposed to the ink over an extended period so a quick
water change would also be effective.

Some might be interested to know that there is some evidence that octopus
ink may affect the olfaction of one of its major predators, the moray
eel, as well as being used as a "smoke screen. Octopuses will ink and then
immediately change its direction to confuse anything that is chasing it.
The ink, though, does not take on the shape of the animal that has been
suggested in the popular literature.

John Cigliano


(M) My fish squirts me to be fed?

by malloy/lyra.scg.hac.com (Jerry Malloy x3337)
Date: 9 Sep 93
Newsgroup: rec.aquaria

In article <26d0j0$c6l-at-usenet.INS.CWRU.Edu> ap932-at-cleveland.Freenet.Edu (Larry Cuy) writes:
>
>Realizing the subject sounds like something out of The Enquirer I
>had what seemed to me to be an amazing experience the other night.
>
<snip>
>
>I felt and heard this water being squirted at me. It came from the
>surface of the aquarium and shot a distance of about 2 feet or more.
>When I looked at where the water was coming from I saw my 
>Canthigster jactator (or close; boxfish I believe) aiming and
>squirting water at me.
>
<snip>
>
>I assume others may have had this experience. If so, I would like
>to hear about it. While I don't think this fish is ready for
>Sea World I am really amazed and pleased at its behavior.
>
>				Larry Cuy
>					
>				ap932-at-cleveland.freenet.edu

	About 13 years ago while I was at UCSD, I had a 30 gal tank stocked with
various animals collected from local tidepools.  Included was an octopus which
had grown from about 2cm (tentacle to tentacle) when collected to about 35cm 
after 18 months.  The tank was in our dining room just behind the chair I spent
many hours studying in.  The octopus had set up a den in some rocks in the center
of the tank but would rest on top of the rocks as long as the room light was on.

	After pulling an all-nighter studying for a p-chem final, I was gathering
my papers and books from the table when they were suddenly getting wet as if 
someone were squirting a water pistol at them.  As you've no doubt figured, 
the octopus was the guilty party.  It had lifted the glass tank cover and was
pumping water from the tank with its' siphon and shooting it about four feet 
across the table onto the papers. 

	Even with my frazzled nerves from too much coffee and no sleep, plus an
octopus trying to extinguish my cigarette, I did well on the exam.  I don't 
believe it was due to hunger (there were still a few hermit crabs crawling 
around) but possibly the octopus was annoyed at being kept up all night by the 
room light.  Thanks for reminding me of the experience, Larry.

				Jerry Malloy

				malloy-at-osprey.hac.com


[M] Octopi

by gseven/lacerta.unm.edu (Roy "Gary Seven" Corey)
Date: 12 Oct 1993
Newsgroup: rec.aquaria

In article <1993Oct11.124855-at-is.morgan.com>, ptang-at-is.morgan.com (Peter Tang) writes:
> I've read that the blue-ringed octopus is poisonous or has a poisonous bite.  I believe it was in an issue of FAMA.  
> 
> 	--Peter

  Yep, it's tetrodotoxin.  The same thing puffer fish have (these are a delicasy
in japan called fugu.  You have to have a special licence to cook them so that
your diners don't keel over.  I wouldn't recomend eating this one though, even
if you could afford it there's more poison in the octopus).  Tetrodotoxin is a
neurotoxin attaching to the sodium gate in the neuron.  It blocks sodium ion
transfer in the neuron and thus prohibits firing (since the ionic charge never
changes).  It is also found in the california newt (though mostly in it's eggs).
It is thought to be an ingredient in the Haitian "Zombie" poison. (In the right
dose it doesn't kill you, it just makes you look dead.  Paralysed.  This dose
is, apparently, difficult to guess at.) 


  





-- 
			   Live from Carina (-at-unm.edu)
			   Roy "gseven" Corey

	"Communication is the staple of an advanced society"


[M] Octopi

by laurence/cco.caltech.edu (Dustin Lee Laurence)
Date: 19 Oct 1993
Newsgroup: rec.aquaria

mvp-at-netcom.com (Mike Van Pelt) writes:

>I believe octopi are short-lived, like a year or two max.

I plan to set up an octopus tank someday, so I've done a bit of
reading on the matter.  I believe that this is true for the species
that we are likely to keep.  The big pacific octopi up in the Puget
Sound area seem to live longer, but I doubt that any of us are
likely to set up a tank for a 125+ pound octopus.

Also, some of the octopi I've seen for sale appear to be temperate
octopi, and being kept at room temperature may shorten their life-
span still more.

O. joubini seems to be the species of choice; they are quite small,
and would probably be a lot happier than a larger octopus in the
kind of aquaria that you're likely to be able to afford.  They also
have the distinct advantage for the truly serious that their eggs
hatch directly into tiny octopi, without the intermediate planktonic
stage of many other species.  This means that it is not nearly so
difficult to provide them with food after hatching; they apparently
begin hunting tiny organisms immediately.

Captive breeding is a particular advantage with octopi, since as Mike
says they are very short-lived.  However, besides the obvious
disadvantage of finding a male and a female and getting them to spawn
without killing each other (octopi are normally solitary, and I don't
know how much room two octopi need so that they won't feel that the
other is an intruder), _all octopi that I am aware of die after
breeding_.  Certainly the females do, usually right after the eggs
hatch (they just stop eating and refuse all food), and the males are
believed to as well (it is more difficult to tell with the males,
since they don't stay in one place to guard the eggs).

There have been some published descriptions of breeding O. joubini;
look for references in a book called something like The Marine
Aquarist's Handbook, Comprehensive Edition.

>I don't know, I wouldn't want something that deadly in my tank, even if
>they aren't agressive.

True, but as far as I know blue-rings _are_ prone to bite.  Most octopi
aren't, probably because most cephalotoxins are pretty weak and not so
useful for defense  (all octopi are poisonous, but generally the toxin
has no effect on humans), but apparently blue-rings are quite aware of
the effectiveness of their bite and will use it readily.  More like
cuttlefish in this respect, I think, though I don't know of any
cuttlefish whose bite is dangerous to humans.

Dustin


>[M] Octopus, Squid and Cuttlefish

by lucas/ucsu.Colorado.EDU (Michael A. Lucas)
Date: Fri, 15 Oct 1993
Newsgroup: alt.aquaria,rec.aquaria




I guess I offered......

I got a whole ton of people who wanted 
me to share my experience with my octopus e-mailing me so I 
figured I'd post it for y'all.  Keep in mind, I've only got 
limited experience with only one octopus so I may be wrong on 
many counts, any advice I give that might be wrong, please 
correct me.  I still have a lot to learn.

Here's a more detailed story (hope I don't bore you).

I have a 38 gallon hex tank with an undergravel (UGF) filter 
running off two 201 powerheads.  I also am running a whisper 
2 (all you filtro-maniacs are gonna have to forgive me, it's 
all I could afford).  I bought the octopus from a local pet 
store (Catfish Charlies for anyone from Colorado) for $29.00.  
He was about 7 inches from tentacle to tentacle.

I had a couple of damsels in the tank and I figured that 
instead of trading them back I'd just let them be the 
octopus's first meal.  The octopus (named Tom-don't ask me 
why) mostly hid under a rock in the tank for the first couple 
of days, then he started coming out a lot.  Once he started 
coming out the damsels started picking on HIM.  They were a 
bit faster than him and they were going for his eyes.  I 
didn't want to risk the octopus for a couple of damsels so I 
took them back to the pet store.

After about a week he was coming out a lot.  He was eating 
well.  He ate goldfish, crayfish, fresh shrimp, crabs, and 
snails.  I could hold a goldfish by the tail and put my hand 
in the tank and Tom would come take the food from my hand!  
The funnest was to watch him eat crayfish.  He would come 
down on them from the top and grab the each pincher with a 
tentacle.  He would then wrap himself around the crayfish and 
bite through the crayfish's shell and poison the crayfish 
till it was immobilized.  Tom would then take him into his 
home (a decorative barnacle shell rock I had in the tank) and 
enjoy his meal.  Later he would toss the empty crayfish shell 
out of his house and I'd take it outta the tank and throw it 
out.

He wasn't shy at all.  Whenever I would reach into the tank 
to clean or anything he would always come out and try to grab 
me.  I never had the guts to let him.  A buddy of mine did 
though.  My friend Mark put his hand in the tank and Tom came 
out and grabbed his hand.  Tom didn't bite him or anything 
but after a minute or so Mark decided that it just felt a 
little TOO creepy and slowly took his hand out of the tank 
and Tom let go.

His color would change like a chameleon (although not 
necessarily to match his environment).  He was usually a drab 
brown but would change to dark brown and black sometimes.  
His texture would also change.  He was normally real smooth.  
He would sometimes change to a real spiny look.  I think all 
octopi change color to some extent.

The end goes like this....I left him under someone else's 
care for a while why I was away.  Turns out one of the power 
heads went out for a couple of days.  This killed the UGF 
which shot my nitrates through the roof.  By the time I got 
back and put him in a friends tank it was just too late.  He 
died after a couple of days in my friends tank.



Well that's the brief version of Tom's story.  I hope that 
helped answer everyone's questions...I'll try and summarize 
everybody's questions below:

1.  Why do they only live for a few months in captivity?
I have heard that their life span in captivity is right 
around a year.  If you have a female and she lays eggs, she 
will die real soon after.  I don't know what there life span 
in the wild is.

2.  Do they breed in captivity?
I don't know.  I know that my tank was definitely not big 
enough for two octopi, and I have no idea how to sex them.

3.  What do they eat?
Goldfish, shellfish, crayfish, fresh shrimp (uncooked).  It's 
best to vary their diet as much as possible I've heard.

4.  Can they be transported?
I transported him from the pet store to my tank, he was fine.  
I assume he was transported from an ocean somewhere to the 
pet store.

5.  Do they ever ink the tank?
YES...Tom inked the tank a couple of times.  It was when he 
was new to the tank and I carelessly let the lid drop on the 
tank.  The noise startled him and he squirted a little ink.  
Luckily it was only a little and my tank was plenty big to 
dilute it.  The ink is poisonous to them and if the spray 
enough and your tank isn't big enough to dilute it, the 
octopus will die.  The ink is protein based and does break 
down rather quickly so if you have an octopus and he does ink 
the tank, you don't necessarily have to do an immediate 100% 
water change.

6.  What kind of filtration do you recommend?
As much as you can afford.  I'd say the absolute minimum is 
what I had.  With less filtration you really need to spend a 
lot of time checking the water and doing water changes.  As 
with any tank, make sure you get any uneaten food out of the 
tank as quick as possible.  The octopus is very sensitive to 
nitrates so watch your them close.

7.  What temperature did you keep him at?
Around 76-78F.

8.  I guess most if not all are marine critters?
Yup.  All are.

9.  How much do they cost?  Are there different varieties?
Common octopus are the plain brown ones.  They get about 12-
16 inches tentacle to tentacle and the cost around $30.00.
Blue ring octopus are very brightly colored.  They are much 
smaller (I think about half the size of commons) and they go 
for around $50.00.  They are very deadly, one bite from a 
blue ring and you have about 5-15 minutes to live.
I've seen a zebra octopus, they arebrightly colored, as big 
as a common-$350.00.
Someone also mentioned something about a fire octopus, I've 
never heard of this, I'd like to hear more myself on this 
question.

10.  Can they have tankmates?
I never tried it.  Most anything that they won't eat will eat 
them.  I was told that If I had a fish in there that was too 
big for Tom to eat and passive enough that it wouldn't eat 
Tom, I could try it.  I never risked it.  I was also worried 
about increasing my bio-load too much with my barely adequate 
filtration.

11.  I was wondering if you secured your tank?
At first I did.  People had told me that they try to get out.  
After a while I started slacking on keeping the tank sealed 
and eventually I just quit even trying to keep it sealed.  He 
never tried to get out....This isn't to say that octopi don't 
ever try to get out.



I hope this answers most questions, this just about exhausts 
what little I know about octopi.  If any of you out there get 
an octopus, I'd love to hear how it worked (is working) out.  
Maybe if we share notes we could figure out how to care for 
these creatures better.  As I said before, I highly recommend 
octopi.  I've yet to see any aquarium creature anywhere near 
as fascinating as Tom was.  I'm picking up another common 
octopus on Monday at a local shop and I've got a Blue-ring on 
order for another tank I have (I have upgraded to a wet/dry 
filter now).

					Good luck to all,
					Michael Lucas
					Universtiy of Colorado, Boulder


>[M] Octopus, Squid and Cuttlefish

by laurence/cco.caltech.edu (Dustin Lee Laurence)
Date: 19 Oct 1993
Newsgroup: alt.aquaria,rec.aquaria

lucas-at-ucsu.Colorado.EDU (Michael A. Lucas) writes:

I mentioned some of what I know in another post, so I'll try not
to repeat too much.  Oh, and I don't claim that everything I say
is correct, just the best I could find out so far.

>1.  Why do they only live for a few months in captivity?
>I have heard that their life span in captivity is right 
>around a year.  If you have a female and she lays eggs, she 
>will die real soon after.  I don't know what there life span 
>in the wild is.

Some possible reasons for the short lifespan:

Both sexes apparently die after breeding.  The natural lifespan of
many species is a year or two, so if the octopus is six months old
when you buy it it may only have six months or a year more to live
naturally.  However, most wild octopi die after breeding, I imagine,
so they may be capable of living longer in captivity with the right
care.

I'm told, without great evidence to back it up, that they are
sensitive to nitrates and to low oxygen concentrations.  They may
be sensitive to levels that most people would consider acceptable.

As I said, here in Southern California I seem to see temperate octopi
from off the coast here for sale (the two sympatric blue-spotted
species, O. bimaculatus/bimaculoides or something similar).  I'd guess
that their lifespan would be a lot shorter if kept at tropical
temperatures.  O. vulgaris is found throughout the Med., so it probably
doesn't mind warm temperatures.  (Anyone know any better?)  O. joubini,
which I mentioned earlier, is found in the Carribean, so it probably
likes tropical temperatures as well.  I'm only guessing on these,
though.  Of course, if you can afford a chiller, that is an entirely
different matter.

Finally, if anyone happens to keep octopi with copper in the water as
people do with fish, or in an aquarium which has had copper in it in
the past, that would probably do them in fast.  They are invertebrates,
even if smarter and more active than most of the invertebrates we are
used to.

>2.  Do they breed in captivity?
>I don't know.  I know that my tank was definitely not big 
>enough for two octopi, and I have no idea how to sex them.

I mentioned that O. joubini has been bred.  They can sometimes be
sexed by the fact that the males may have an enlarged sucker or two near
the base of an arm or two, perhaps two or three times larger than the
rest.

One arm on the males is adapted for transfering sperm, something like
the third arm from the front on the right (but I'm probably wrong on
this one).  I'd tell you what the technical term is, but I'd undoubtedly
butcher it--hectocotylus, or something.  Anyway, I don't think that the
modification is obvious, and I wouldn't know what to look for, so I
don't think that this would be a useful technique.

>3.  What do they eat?
>Goldfish, shellfish, crayfish, fresh shrimp (uncooked).  It's 
>best to vary their diet as much as possible I've heard.

I would avoid the goldfish, actually.  Freshwater and saltwater organisms
have different nutritional value--freshwater fish have a greater fat
content, I think, and different amino acid ratios.  Anyway, at the very
least make the majority of the diet marine in origin.  That is true for
marine carnivores in general, and I assume it is true for octopi as well.

>The ink is poisonous to them and if the spray 
>enough and your tank isn't big enough to dilute it, the 
>octopus will die.

Some say the ink is poisonous, some say not.  Even if it is not, it
wasn't meant to be released in a tiny closed system, and if there is
enough ink the octopus may suffocate from its own ink.  Remember, they
may be more than usually sensitive to low oxygen already.  Whether or
not the ink is actively poisonous, it apparently can but is not
certain to harm the octopus.

I personally would insist on having a protein skimmer, because a skimmer
will probably pull ink out rather effectively.  I don't know if it would
be fast enough to save the octopus if it released a huge load if ink,
it sure would help.  Have a drain into a big container, because the
skimmer will probably go nuts if the tank is full of ink.

>6.  What kind of filtration do you recommend?

>The octopus is very sensitive to 
>nitrates so watch your them close.

This is consistent with what I have heard.  I would consider a protein
skimmer mandatory for this reason as well.  They are messy carnivores,
and you want to pull as much out of the water as you can before it
begins to break down, so you don't have to deal with the nitrates as
well.  Get the skimmer first.

If you can afford it, I would probably set it up as a berlin reef tank,
but adapted for the octopus.  However, most of us probably can't afford
to go this route.  I suspect that a trickle filter would be a good
second choice, especially if I am correct and they are sensitive to low
oxygen concentrations.  I'd avoid the undergravel filter if possible,
both because it will clog even faster than usual with uneaten food and
because the octopus might take it in mind to re-arrange things in a way
which would uncover a portion of the filter plate and diminish its
effectiveness.

>11.  I was wondering if you secured your tank?
>At first I did.  People had told me that they try to get out.  
>After a while I started slacking on keeping the tank sealed 
>and eventually I just quit even trying to keep it sealed.  He 
>never tried to get out....This isn't to say that octopi don't 
>ever try to get out.

Apparently this is highly variable.  I have heard stories of determined
escape attempts, including one by Cousteau which is presumably accurate.
In addition to their famed ability to squeeze through tiny holes, they
are amazingly strong and dexterous.  They are particularly strong when
pulling, and can (I am told) easily exert several times their body
weight this way.

>Maybe if we share notes we could figure out how to care for 
>these creatures better.

I have a few things archived so far, and will archive whatever else
people want to send me on this subject.

Dustin


Blue-ringed octopus

by mvp/netcom.com (Mike Van Pelt)
Date: Tue, 16 Mar 1993
Newsgroup: alt.aquaria

In article <C3yFHK.n4F-at-news.cis.umn.edu> peschko-at-orca.micro.umn.edu (Edward Peschko) writes:
>A related thought -- how dangerous are blue-ringed(?) octopus(es)?

Very.  With them, it's not a question of whether you're alergic.
Their bite is a very potent neurotoxin.

>I was thinking of getting one -- if they are potentially fatal.. forget it.

Forget "potentially"... their bite is immediately life-threatening.
As in CPR and heart-lung machine until the toxin wears off, otherwise
you assume room temperature.  One case someone wrote about here, a
fisherman put one on his hand, and didn't know he'd been bitten until
he took it off and saw the bite.  He survived, after spending four
hours or so on a heart-lung machine.

I don't know if there are long-term effects (other than brain damage if
someone doesn't start CPR soon enough, of course.)  Some other
neurotoxins, like poison-arrow frog toxin, have little or no long-term
effects if you survive at all.  Then again, I think the frog's toxin
only affects voluntary muscles and breathing, while I get the impression
the blue-ringed octopus toxin also paralyzes heart muscle.  Does anyone
have more info on this?

-- 
"The American Republic will endure, until        Mike Van Pelt
politicians realize they can bribe the people    mvp-at-netcom.com
with their own money."  Alexis de Tocqueville


Blue-ringed octopus (WARNING!!!!)

by andrewt/cse.unsw.edu.au (Andrew Taylor)
Date: Wed, 24 Mar 1993
Newsgroup: alt.aquaria

In article <ZJHZB1FS-at-cc.swarthmore.edu> wells-at-cs.swarthmore.edu (Daniel Wells) writes:
> What I've read (in several different places) is that these
>octopi kill several people annually in Australia with their incredibly 
>poisonous bite. I've also read that they are the only octopus that is terribly
>poisonous (the rest are not any much worse than a bee sting, unless you happen
>to be allergic.) 

I can't remember when the last death from Blue-Ringed Octopus bite was.
The extreme toxicity of the Blue-Ringed Octopus was only discovered about
20 years ago.  I'd expect most Australians are aware now of its toxicity
and deaths will likely occur only about once every ten years, if that.

Only the two species of Blue-Ringed Octopus are *known* to be dangerous to
humans but I'm sure not all species have not been tested.  I'm very
careful not to let any octopus bite me.

Andrew Taylor


Octopus in 5gal?!?!

by mrb/oregon.uoregon.edu (Michael Robert Beale)
Date: 20 Apr 1994
Newsgroup: rec.aquaria

In article <1994Apr11.034823.1-at-opal.tufts.edu>, etsang-at-opal.tufts.edu
wrote:
>
> I am thinking of keeping an octopus and would like to know whether they are
> hardy or not.  I plan to keep it in my 10-gal tank with a Fluval 2 and
> aeration only.  Will that be enough filtration?

I've kept octopus on a number of occaisions, in a variety of set-ups - with, of course varying success.  They are endlessly amusing but completely unforgiving of water quality variations.  They are quite sensitive to elements of the nitrogen cycle and even more unforgiving of salinity changes.

Primarily for this later reason, I would not recommend keeping an octopus in a 5 gallon, independant system.  My most recent (and successful) system is a 12 gallon specialty tank, which is fed from a branch in the filter system for a larger reef system.  The 12 gallon hexagon has it's own overflow, and lighting, but shares a trickle filter and protien skimmer.

This particular system has worked well for me because it allows me to keep Vathek (this particular octopuses name) in a small seaprate system and not mourn the waste of space because if incombatability problems.  (I have found no motile tank mate for octopi which will not eat, or be eaten by, the voracious little buggers.)  I built a series of small caves below a miniature reef wall made of small pieces of live rock.  Vathek has a stylish home, and I have a small tank in which to cultivate all those little

 
 buds and offspring I find in the larger tank.  It seems important to provide the stability of a larger filter system and water mass for extended success.

By the way - it has worked well for me to collect small shore crabs and keep them in a breeder trap in the larger tank for feeding.  I am in Oregon, but the cold water crabs seem to adapt just fine to the week or so I keep them around.

If you get really serious about Octopi, try a cold water tank and small temparate species.  While studdying at the Oregon Institue of Marine Biology, we kept several octopus together in a very small tank connected to our water tables.  I've never tried this with tropical species but I wonder if the reports of fatal territoriality are true.

-Larry Hoffman
**


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