An aquarium includes an outer housing including a bottom wall and a side wall extending from the bottom wall, the outer housing defining a first interior tank volume to house water. The aquarium also includes a base disposed inside the first interior volume and coupled to the bottom wall, the base including an aperture. The aquarium also includes an inner housing coupled to the base, the inner housing defining a second interior tank volume to house water, wherein the aperture provides fluid communication between the first and second interior tank volumes.
