An aquarium, especially one used to keep fish.(noun)
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Use "fishtank" in a sentence
"The ubiquitous actor Denden plays Murata, the owner of an exotic-fish shop staffed with adolescent females uniformed like the fishtank equivalent of Hooters Girls."
"Almost thought the window in the first photo was a wall-length fishtank! maha"
"I had considered doing this with my old fishtank, but it leaked and was thrown in the garbage."