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Tank Suitability

Lee Wayward

Oct 23, 2015
Hello all!

I'm hoping to set up a tank for a baby octopus.

I was wondering if one of you could kindly advise on suitability of this model:

I'd like to fit it with a Jebo filter I've purchased:

and a protein skimmer I've also obtained.

I've read a wealth of information, including the ceph-care-equipment-list but I'm still somewhat lost - I was thinking of populating the tank with some live rock, dimmed / filtered lights and keeping zeba danios in there for a couple of months before introducing a baby octopus. From what I've read, I should get into the habit of cleaning the tank and filters every other day; taking regular copper readings (hopefully zero) and conducting various other regular water tests before thinking about buying the octopus.

Thanks for taking the time
A few suggestions. I'm assuming the "240" is liters. So not quite 65 gallons. This might be acceptable for a smaller tropical/dwarf octopus, but probably a little small for one of the bigger varieties. The filter you linked is a canister filter, which while great for FW tanks, isn't as great for marine.( I've tried). You would be better served fitting a second tank inside the stand and building a sump. You will want the tank and rock cycling for a good 3 months before adding the octopus. As zebra danios are fresh water fish (and Ive not heard of anyone acclimatizing them to SW) that's probably not advisable. However, fishless cycling is the norm these days. Just adding the live rock (or if you want to help it along, a small piece of standard grocery store shrimp) will do the trick of getting the bacteria going.
As @ekocak mentioned, this is a freshwater setup. There are two issues with converting a used fw to sw. One there is no sump so octo-proofing (sealing it up to prevent escape) is more difficult because of the needed external filtration and two, the normal use of copper based medication. Strong anecdotal observations suggest that copper meds invade the silicone seals on glass tanks and then leach copper back into the tank, making it unsuitable for corals and invertebrates. The amount of copper needed to pollute a tank is too small to be detected by all hobby and most lab test kits. Here is a post that links useful informational for new keepers.

A typical saltwater set up (vs freshwater) will have an additional tank (typically kept in the bottom of the cabinet) called a sump. Water is gravity fed to the sump and pumped back to the display. In Europe, a canister filter is often used for the return but in the US a separate pump is most common. The sump provides extra filtration and a place to put the filtration hardware (filters, skimmer, sometimes algaes to minimize nitrate, sometimes live food). The best way to send display water to a sump is to have the tank drilled to accept a bulkhead, contain it in a weir and connect tubing to allow the water to dump into the sump (I place a sock filter with charcoal at the mouth of the tube for particulate and chemical filtration but there are alternative filtration methods. Take a look as some to the tank buildouts that are linked in this thread.

Cycling can be started with live saltwater fish but there are numerous reasons not to use this method. Fish should never be kept with an octopus. They are not a normal food and tend to pester and stress the animal. In the wild the octos can often avoid them, not so in a tank. Typically the octopus will kill the fish but only eat the soft underbelly but it may suffer stress or physical damage before the fish die. Fish can be removed before adding an octopus but at the highly likely risk of having to disassemble the tank to catch them.

The preferred method is to use a fishless cycle. This typically involves obtaining fresh live rock (cycled or uncycled), adding safe inverts after the initial cycle and heavily feeding the inverts to grow the bacteria needed to handle the ammonia output of a large animal (octopus waste is similar to that of a large fish). Active cycling to accommodate the load takes a minimum of 3 months.

You will not test for copper. As I mentioned, the amount of lethal copper is too small for most detection methods. You WILL test for PH, ammonia and nitrite.

If you will be ordering an octopus from your local fish store, it will likely be Indonesian and suitable for your tank. Your local O. vulgaris needs a MUCH larger aquarium. This post may be helpful (more geared to the US but imported octopuses are included and would be the same).
Quick question, do you HAVE to wait three months. Because studies have been done to prove the water doesn't absolutely have be reef quality, and the only reason people say this is because reef tanks generally have cooler water, with no ammonia or nitrites, but can live in nitrates up to 100ppm.
You are not striving for reef quality. You are building an environment for a large predator and you need to build up enough bacteria to handle the waste from that predator. Yes, it does take longer to develop the needed bacteria for a cold tank and a longer active cycle would be recommended. Cycling is NOT a passive waiting period (albeit it can be boring to many). After roughly a month with live rock you should be able to add a few interesting inverts, start learning how to maintain the tank (a weekly commitment to water changes and daily checks for freshwater top off). Please commit to reading some of the material we have collected and discussed. There is a link to cycling discussions and information in the linked beginners thread but I will include it here for ease of access.

Please be sure to check the success with your interests of anyone suggesting shortcuts as well as a complete description of their maintenance and environment (you cannot chose one from column a and one from column b to be successful). Labs and public aquariums have very different set ups that most home environments cannot replicate.
Thank you for the prompt and detailed feedback.

I clearly need to re-think and try again.

I'm going to bury my head in some articles and hopefully suggest something more suitable (/d).