As for keeping them in captivity, it's already been mentioned that they
are amazing escape artists capable of squeezing through seemingly
impossibly small cracks. I'd like to add to that:
They are also freakishly strong. Don't think that even a small one can't
push open a tank lid held down by a brick and strip lights, for it's
easy for them. However, their pushing ability pales in comparison to
their pulling power. I've had them literally pull their filter equipment
apart from inside the tank. One even died this way; smart enough to
figure out how to disassemble it's filter, it wasn't smart enough to
figure out how to put it back again before it suffocated.
Moon already mentioned that they need very good filtration, and this is
very true. They can't survive a tiny fraction of the pollution a fish
can. To make matters worse, they make a much, MUCH bigger mess than any
fish ever could.
Waste treatment isn't the only factor, though. They need a lot of oxygen
and good water flow. An octopus can die in a power outage in only a
couple of hours versus a couple days for fish.
Back to the strength, choose your tank decor carefully. If you decide to
move something and the octopus decides that that something needs to
stay, ( and it will ) then you will have a lot of trouble getting it
back out again. Also, be aware that an octopus can very easily take that
nifty seashell you gave it and use it as a sledgehammer to smash the
tank's glass walls.
For the first few days, your octopus will be very shy. This won't last
very long, though. Once the beastie figures out that YOU are it's
feeder, ( and it will ) then it will come out whenever it sees and
recognizes you. This will be fun, but it will present a new challenge-->
opening the tank to feed it. The second you raise that lid, five or six
tentacles will lunge outward to grab whatever goodies you have brought.
if some of those tentacles should grab your figers, you may have a
problem. If the octopus is distracted enough by the food, it will let
you go and slink away to enjoy it's meal. If not, you will be in a
tug-of-war unlike any you've ever before experienced, and with some
pretty high stakes--> pull too hard and you can injure your pet, but let
it get too much of a grip and you could get bitten.
Ah, the octo-bite...
While only a few octopuses have strong enough venom to kill you, they
can all pack a whallop nonetheless, and that beak of theirs produces a
deep, curious wound that just won't stop bleeding, it seems.
One last thing: They are very intelligent, and they have very good
eyesight. If you have other tanks around, don't be surprised if you
octopus tries it's level best to leave it's own tank in order to feast
upon the denizens of nearby tanks that it can see. They do this all the
time if their tank is not secured, no joke.
Some good news that makes reading this whole post worthwhile:
They aren't THAT smart. There is a very simple way to solve most of
these problems and make your tank escape proof. In a word: eggcrate.
That's right; the "eggcrate" lighting diffuser stuff that we use so
often in reefkeeping for various things is also good for stopping
octopuses. It sounds crazy, but they get confused while trying to go
through the holes, and wind up trying to go through numerous holes at
once, ultimately getting through none of them. Really, it works! Put a
layer across the tank top under the lid, and your octopus won't escape
even if you leave the lid open.
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