Fish Tank
Water Tank
noun
A tank of water can be used as a fish tank or a water tank for drinking. It really only depends on you and how many fish you have.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
どのくらい頻繁に水槽の掃除をしますか。
How often do you clean the fish tank?