水族馆 (shuǐ zú guǎn) means “aquarium”

More examples

水族馆里有很多海豚。shuǐ zú guǎn lǐ yǒu hěn duō hǎi tún

There are many dolphins in the aquarium.

A place that brings many kinds of water life together so people can watch them from land.

鱼缸yú gāng: A water-filled container that holds fish so they can be seen from outside.

供人参观鱼类等水生生物的公共场所gōng rén cān guān yú lèi děng shuǐ shēng shēng wù de gōng gòng cháng suǒ

The parts 水 (shuǐ, "water") + 族 (zú, "group") + 馆 (guǎn, "hall") combine to name a hall where aquatic life is gathered for visitors.

The contrast between 鱼缸 (yúgāng, "fish tank") and this word helps separate an object that holds fish from a place designed for visitors.