• 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.

75 gallon good size?

Mike D

Pygmy Octopus
Aug 1, 2004
First off i am new to the site..

i dont have the tank set up right now.. im in the process of moving my room..

But i have been looking for something different to put in my 75 gallon tank when i set it up.. and i would love to put and octopus in it.. but i have a few questions

Can they be fed feeder fish when they get bigger? i have read conflictiing things on this
also what is a good size tank to set up as a feeder tank for clams hermit crabs and such?
how would i set the tank up? i have heard they love to move things around. pics of your setups would be helpfull.

Try looking through the Ceph Care section.... Just about every question has probably been asked.... Also check out the Equipment list and a lot of the tanks in the Octo Database have pictures...

Hope that Helps
:welcome: to TONMO!

Feeder fish shouldn't be fed to a ceph since those fish could have been in stanks treated with copper, and since guppies, rosies, feeder goldfish, etc. etc. aren't as sensitive to copper they can stand it then when your ceph eats the fish it also gets the copper.

I'll be using my 20 gallon in my room for a feeder tank.

I've used a glass bowl available from pet shops for keeping fiddler crabs. It has a diameter of about 16 inches. I have a rock for them to climb out on, some shells to hide under. I fill it with about one inch of water, half salt water, half distilled water. That's worked fine and I've kept some crabs a long time in this bowl. Have to change the water often, but that's easy to do.


Hi Mike, is it an old tank? Have you used any copper treatments in your tank before now as this may make it unsuitable for cephs??

i have never used any copper in the tank. as a matter of fact it isnt even set up for salt water yet because i am in the process of moving my room...

also is there a way that i can test teh water for copper before i put in the octopus? i called all around today to try and find any place that sells RO/DI water... is this going to be a problem? or can i cycle my tank longer and get the same effect that the RO/DI water has.. or can i make my own?

For feeding i live in massachusetts and my parents go up to maine every other weekend during the summer.. could i have them bring me back small crabs, muscles. and snail that they find at the beach?
Hi Mike,
I can't believe that you can't find RO/DI water in Massachusetts. Most fish stores sell it, I think someone found that Culligan's (the water supplier) sells it, heath and gourmet stores sell it - ask first for purified water, then ask how it's been purified.

You can also buy your own RO/DI unit and make your own purified water. But you need this water - adding chemicals or such to the water won't have the same effect.

Yes, you could put your parent to work hunting for small crabs, mussels, and such along the shore. They should plann to bring them back in a cooler on ice, and you could freeze the crabs you won't use immediately.
I don't know about keeping New England sea life alive, but your water is quite cold there and I don't think y ou could reproduce it.

You can buy copper tests or your local fish store should be able to test for you. Has this tank had another owner besides you? Copper is deadly to an octo, so it's very important to assure that there's no copper in the tank. If there is copper, there's not much you can do to remove it.

im the only owneer of the tank.. i used to keep lizards in it then i kept some freshwater fish..

and now it is sitting empty in my room

I couldnt find the water any where i am very limited to pet stores around me...

will tap water work if there is no copper in it?
Wy don't you try to look for RO water = that's the reverse osmosis process.

What do your LFSs use for their fresh water?

What does Walmart sell in 5 gallon jugs for purified water?

I use distilled water for my top off, for instance.

Very few people can use city water - it tends to vary in quality during the year, too. It would be better to buy an RO/DI unit and filter your own water.

i dont have city water i have well water....

What does Walmart sell in 5 gallon jugs for purified water?
Does that mean that tehy water in the 5 gallon gugs will work for an octo tank? kind lost me there
Then you'd have to have your well water tested, or maybe you've already done that.

Someone else was searching for RO/DI water and found it, or at least RO water in some common stores - I think it was Walmart. You've have to see what the label on their jugs says - how it was purified.

will it say RO or DI purified right on the bottle?

also i have a filter with dual bio wheels on it think it an emporor filter? it hangs ont eh back of the tank.. will i be able to use this for a filter if i get another one of those? it is rated for a bigger tank.. plus i will have a protein skimmer on it as well.

the filter is the Marineland Emperor 400 Filter System.. also if this will work what is teh easiest way to make it escape proof since there is a part of teh filter that hangs into the cage?
Where do you live in Mass.? You might be able to go down to the Cape and find some stuff. It's closer and the water is warmer, so you don't have to worry about the crabs dying from stress because the water is slightly warmer. Since your parents only go up to Maine in the summer, do you have a food source during the winter? Just something to think about (easily I'm sure).

And the RO water, I personally think it's easiest and less of a headache to just buy an RO unit. You don't have to lug around 5-gallon containers 5 times each in order for you to make seawater. And in case of an emergency, during a time when your supplyer is closed lets say, you don't have to worry about getting water. Just my 2 cents.
In answer to your first question, the water is marked "Reverse Osmosis" and "Deionized" usually - we refer to RO and DI.

And, you can buy the RO and RO/DI units on the web, from the big aquarium suppliers. I know that Kent Marine makes them, for instance. Be sure to get one for aquariums. But there may be one problem - water pressure. People here in Dallas are advised to run their units at night, when water pressure is greatest. And waste water is produced as well, that you can use on the garden.

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