i have a 90 gallon tank and 2 filter/pumps that can handle 150 gallons each... how frequently would i need to change the water? since it is a fairly large tank, i'm thinking 25% every 3 weeks should do it.


i've heard that it is nearly impossible to tell between a venomous octopus and a non-venomous one... is that true?

Hi Gohan,

That's a nice big tank! You don't say what kind of filtration you're using, but most people with octopuses use a protein skimmer in addition to other sorts of filtration.

There are various theories on water changes. The most common seems to be 10% every week or 20-25% every couple of weeks.

Your question about poisonous ocotopuses: All octopuses have venom, because that's the way they kill their prey. The ones sold as pets are not a problem, except for one (Blue Ringed Octopus) that is sold very rarely. Please look at a reply I did for a mail bag enquiry on September 16,2002 (http://www.tonmo.com/letters.php) for more information on this subject.

Nancy

i was thinking of putting a vulgaris in the 90 gallon tank...how big do they get?

mantle to 25cm and arms to 100.. big octopus potential!

Cheers
C

hmmm, 90 gallon tank sounds too small for that... what would fit into a 90 gallon tank comfortably?

Probably better go for something like Octopus bimaculoides which is diurnal and gets to about 12cm mantle and 35cm arms, much better all round :)

C