Fish tank
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A fish tank is a glass container you keep pet fish in. You can also keep turtles, hermit crabs or even mice, lizards, frogs and snakes in a fishtank.
Obviously, if you are keeping land animals in a fish tank you don't fill it with water, you put dirt in the bottom and grow plants. A fishtank with plants in it is often called a vivarium. You usually keep mice in a fishtank with sawdust at the bottom instead of dirt, so you can regularly change the sawdust to keep it clean.
