An aquarium is a glass- or plastic-sided tank used to house and display live fish or other aquatic animals and plants. The aquarium size/capacity is usually measured in gallons of water, such as a 20-gallon tank or 40 gallon tank. A saltwater tank is required for fish from the ocean; a freshwater tank is used for tropical fish and goldfish.
An aquarium for tropical fish would typically include the fish, water, a filtering device and an aerating device to keep the water filtered and oxygenated, a heater, an overhead light, small rocks, gravel, or sand on the bottom of the tank, an assortment of plants, and possibly other decorations. An aquarium for small turtles would include an underwater area and an above ground area such as a rock.
There are also much larger aquariums with exhibits of larger animals on public display, such as sharks and penguins. Examples of larger aquariums are the Monterey Bay Aquarium, Marine World and the San Diego Zoo, where larger marine animals are housed.
- http://www.mbayaq.org/ - Monterey Bay Aquarium