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50, 55 or 65 gallon tank?


Pygmy Octopus
Apr 17, 2004
Hi! I am considering my tank purchase for an octopus-only (bimac) tank. I have read the "Ceph Care Equipment List" and noted that a 50 gallon tank is the minimum recommended. I was considering a 65 gallon tank for the increased water capacity, but the 55 gallon tanks have a greater width, although less capacity than the 65. Can anyone give me some feedback as to what they think would be the better tank choice?

50 gallon: 36x18x18
55 gallon: 48x13x20
65 gallon: 36x18x24

:welcome: to Tonmo, Slam!

The 55 gallon would be the best, because if your measurements are Length x Width x Height, than the 55 gallon would have the most bottom space for the octopus to roam (octos usually don't go to the top 2/3 of your tank). :wink:
Ok, so then I am assuming that a 75 gallon with a footprint of 48x18x20 (LxWxH) would be still better. I seem to recall something about just getting the largest tank that you can fit/afford. I was trying to avoid a tank with a 48" length, but if it will make my future pet happier, I suppose it's the way to go.

Hmm, this is a tough one.

This is the number of square inches of bottom area:
36 x 18 = 648 sq in
48 x 13 = 624 sq in
36 x 18 = 648 sq in

There isn't too much difference in area (only 24 sq. in). I think the 36" x 18" is a shape that's easier to work with, to have live rock and a beach area, but the longer one isn't impossible - you'd just have to arrange it a bit diffently.

Another consideration is whether you can reach into the tank if it's the tallest tank, or would have to stand on something. It's a big advantage, expecially for interacting with an octopus, to be able to reach into the tank easily.

It's true that octopuses generally stay in the lower half, but when they are older, they may use some of the higher areas for playing with you and for hanging on the glass (see pic)

All three would be OK, the larger ones provide extra water space, but get one you can reach into easily.

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