• Looking to buy a cephalopod? Check out Tomh's Cephs Forum, and this post in particular shares important info about our policies as it relates to responsible ceph-keeping.

thinking bout geting an octopus...newbie Q's


Jan 13, 2003
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.

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


Shop Amazon

Shop Amazon
Shop Amazon; support TONMO!
Shop Amazon
We are a participant in the Amazon Services LLC Associates Program, an affiliate program designed to provide a means for us to earn fees by linking to Amazon and affiliated sites.