A complete set generally consists of the glass tank itself, a matching cover with lighting, an interior filter, a heater tailored to the tank size and a thermometer for monitoring the water temperature. You will often find a complete aquarium with other accessories such as a water treatment agent,water quality testing items and fish food. For your new aquarium, you also need a lot of accessories, including flooring, aquatic plants, decorative elements such as roots and hideaways for your decorative fish, prawns and crabs.