An aquarium is a glass container or building where fish and other water animals are kept so people can observe them.

In your home, an aquarium might be a small glass tank sitting on a table, filled with colorful tropical fish, plants, and decorative rocks. The water needs to stay clean and properly filtered, and different fish need different temperatures and amounts of salt in their water. Keeping a home aquarium teaches responsibility: the fish depend entirely on their caretaker to feed them, clean their tank, and maintain the right conditions for them to thrive.

Public aquariums are enormous buildings with massive tanks that can hold thousands of gallons of water. These aquariums display creatures from around the world: sharks gliding past enormous windows, jellyfish floating like alien spaceships, sea turtles paddling through artificial coral reefs, and octopuses solving puzzles. Scientists at public aquariums study marine life, help protect endangered species, and teach visitors about ocean conservation.

When you stand in front of a large aquarium tank and watch a school of fish turn and shimmer in unison, you're seeing a tiny piece of an underwater world that covers most of our planet but remains largely hidden from human eyes.