When I said they prefer some height, I meant I wouldn't get something like a 33 L, that is very lacking in the height department. I think that the cuttle would be plenty comfortable in any tank with a decent water volume and some room to move around, but if you put them in a tank with little open space they will be less active and harder to find. Nautilus need a long tank so that they don't slam into the sides - which is the same reason they need a tank with some width to it as well. Height in an aquarium is really the least important for a Nautilus because in a shallow tank they do not have any greater risk of running into anything except for a pile of live rock. However, in the wild Nautilus endure incredible changes in depth during the night (when they 'surface'), and I'm sure they wouldn't mind having some room to make use of their gas chambers. A standard 75 gallon (48Lx18Wx20H) is the minimum tank recommendation for a Nautilus.
Let's not get off topic though
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