A colorful mix of jellyfish from all over the globe are on display in a new exhibit at the Vancouver Aquarium, in Canada. The tank contains around 2,000 spotted jellyfish and many species that are rarely seen at the aquarium. Between 1,000 and 1,500 different species of jellyfish are known today. Jellyfish are the oldest multi-organ animals in the world. They have roamed the sea for at least 500 million years.