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Running tank with fresh seawater


Jul 3, 2016
We are considering having a new guest in our home - an Octopus - and have a basic question but one not so typical:

We live on a boat in Alameda, California.
My thought is that we can run a small water line directly from below the boat and up to the tank and back. It is in an area that gets good flow so it is generally the typical Bay Area water temp and not appreciably higher or in any way stagnant.

We can easily trap crab but perhaps not tiny crabs - I can look into this.

Anyway - you get the gist of my thinking and any thoughts from you experts would be appreciated.


Staff member
Sep 4, 2006
Definitely and interesting and unique idea. My one concern is the gas from the boat engine (assuming you do not live on a sailboat) polluting the immediate surrounding water. I would suggest using some kind of prefilter for the water as well. Coastal public aquariums have used water piped in and filtered for their large tanks with success.

Live food for most tanked octopuses needs to be pretty small. They do capture live crabs of considerable size in the wild but have much more room to maneuver and retreat than it would have in a home/boat aquarium. You CAN offer pieces of fresh crab. I hunt loose blue crab claws when our local Asian market has live crabs then take them home and freeze them to feed the octo. Feeding whole crab is quite messy and can easily pollute the tank so I would recommend offering just the meat in sections (claws can be offered with the shell but be sure to remove the remains within 24 hours). If you have a freezer aboard, you can freeze the claws and probably the raw body meat but discard the rest as it will poison the meat.

Mel Cheal

Jul 1, 2016
I'm far from an expert, but here are my thoughts. I like the idea, a lot. And considering you live on a boat it makes more sense than doing it the "typical" way. Going off what DWhatley said about aquariums, the Kanaloa Octopus farm uses piped ocean water, but its from deep down, not near boats (speaking of which, they also go out and catch crabs nightly to feed the octos).
As long as the water is pollution and heavy metal free (I like the idea of filtering it first, and I would also test the water for any heavy metals), I don't see why it would be an issue. I'm assuming you are thinking of keeping a local species?


Blue Ring
Jun 30, 2016
I use NSW in my main DS tank, def a fan if your collection site is clean. Its recommended collecting on the incoming tide supposed to be less polluted. I just filter the NSW through a micron sock and carbon get it to temp (as tropical set up) and use straight away. (Suppose you will not need to warm if it's a native but you do need to ensure stable temp). But def use a micron sock before pumping it straight in and keep carbon running at all times.
Loads of people use NSW and swear by it, I find most advocates don't fuss with it to much and get great results. BUT a reliably clean collection area is key and apparently the further out to sea the better, although saying that I collect mine from a creek just putting a pump over the garden wall.
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