• 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.


Sep 15, 2003
I am new to tonmo and aquariums. I have to be able to answer some questions before I can actually get the tank and critters, etc. Does coral stop growing once it fills a space or does it need to be divided or something? What are the necessary tools for measuring water quality and what are the qualities that the water should be at before getting a ceph? How big does a ceph tank need to be for a ceph about 4 or 5 cm total length? How long should I wait to cure the tank? How much does it cost to maintain a ceph tank? Any answers to any of these questions would be GREAT! Thnx in advance!
Hi Rachibelle,

Those are a lot of different questions!

The size corals grow to depends on the species. You can pick smaller ones for your space.

The tools you need for measuring water quality are test kits (nitrites, nitrates and ammonia), something to measure pH (kit or pH meter), a way to measure salinity. You might want to visit your local LFS and have a look at some of these things.

Please be more specific about the ceph you want to get. Elsewhere you've mentioned the bobtail squid. Is this what you're thinking of?

THe cost of maintaining the tank will be the cost of food and the cost of saltwater (RO/DI water plus salt, or buying saltwater from the LFS) for water changes (about 5 gallons/week for a 50 gallon tank). There are a few minor costs like adding some fresh carbon from time to time. You will need to research these costs yourself, since they can vary.

You might want to let us know where you live - do you have a source for getting the squid?

Also, have a look at Colin's Equipment List under Ceph Care on the Site Menu

Hope that helps,
Hi Nancy

Yes, I am hoping to get a bobtail squid, altho it is not really a squid. I am located in Austin TX but have not looked into how to get my bobtail, as I am trying to convince my parents that I can handle a tank. Thnx for all the help!
If you are at a school or university, you can ask the NRCC to send one to your school or university saying that you're taking a marine biology course or something
Hi Rachibelle,

My tank is 46 gallons and I suppose I spend a couple of dollars per week on water and salt. REcently I'm having to replace my test kits, but if you amortize that amount over a year, it isn't much.

I bought almost everything I needed right at the beginning, including accessories like an algae magnet and algae pads, a net, salt, etc., so I didn't have to buy these as I went along.

joel_ang said:
If you are at a school or university, you can ask the NRCC to send one to your school or university saying that you're taking a marine biology course or something
lol that's what I did and it worked out great for me, but I told them to send it to the lab at my uni, include the address--important!!
Rachibelle you can look up my past posts to see what I did since im too lazy to look up my post's, you can do a search for it. :)
Im still learning cephs but I can answer the Coral question, as I keep reef tanks. Coral growth depends on a LOT of factors. Quantity and quality of light is a primary factor. Depending on the coral, trace elements in the water, as well as water movement play an important role. Most corals object to trampling, even by tiny crabs and shrimp, I can not imagine the beating an octo would deliver. I do think there is a lot to learn keeping corals. The corals in my tanks tell me something is wrong with the water LONG before any test kit will. They are task masters when it comes to tank maintenance, and will help develop good maintenance habits. I am hoping that someday soon, these habits will keep an octo happy.

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