An aquarium (plural aquariums or aquaria) is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants. The term combines the Latin root aqua, meaning water, with the suffix -arium, meaning "a place for relating to".

An aquarist owns fish or maintains an aquarium, typically constructed of glass or high strength acrylic plastic. Cuboid aquaria are also known as fish tanks or simply tanks, while bowl-shaped aquaria are also known as fish bowls. Size can range from a small glass bowl to immense public aquaria. Specialized equipment maintains appropriate water quality and other characteristics suitable for the aquarium's residents.

In the Roman Empire, the first fish to be brought indoors was the sea barbel, which was kept under guest beds in small tanks made of marble. Introduction of glass panes around the year 50 allowed Romans to replace one wall of marble tanks, improving their view of the fish. In 1369, the Chinese Emperor, Hóngwǔ, established a porcelain company that produced large porcelain tubs for maintaining goldfish; over time, people produced tubs that approached the shape of modern fish bowls. Leonhard Baldner, who wrote Vogel-, Fisch- und Tierbuch (Bird, Fish, and Animal Book) in 1666, maintained weather loaches and newts.

Takashi Amano (天野尚, Amano Takashi^?) is a photographer, designer and aquarist. His interest in aquaria led him to create the Japanese company Aqua Design Amano.

Takashi Amano is one of the most influential people in the freshwater aquascaping community. He can largely be credited with introducing Japanese gardening concepts such as Wabi-sabi and Zen rock arrangement to the aquascaping hobby. His tank compositions involve intricate, and typically asymmetrical (though balanced) arrangements of aquatic plants often augmented by river rocks and driftwood. His aquascapes are notable in that they often mimic nature in their appearance, and can be regarded as a form of art.

Amano is the author of Nature Aquarium World (TFH Publications, 1994), a three-book series on aquascaping and freshwater aquarium plants and fish. He has also published the book "Aquarium Plant Paradise"(T.F.H. Publications, 1997).

Amano can also be credited with popularizing the use of Glossostigma elatinoides and Riccia fluitans in aquascaping and the use of shrimp as a means of controlling the growth of algae.