Common name: True Jellyfish
Scyphozoa, commonly known as true jellyfish, are a class of marine animals within the phylum Cnidaria. They are predominantly found in the open ocean and are known for their distinctive gelatinous bodies and umbrella-shaped bells. These fascinating creatures are mostly free-swimming and use their rhythmic pulsations to navigate through the water, although they are largely carried by ocean currents. One of the most striking features of Scyphozoa is their tentacles, which contain specialized cells called cnidocytes. These cells are equipped with nematocysts, capable of delivering a stinging sensation to capture prey or as a defense mechanism.
True jellyfish vary greatly in size, with some species like the lion's mane jellyfish (Cyanea capillata) reaching up to 2 meters in diameter, while others are much smaller. They exhibit a wide range of colors and patterns, making them a visually captivating addition to public aquariums. However, due to their stinging capabilities and specific environmental needs, they are not typically kept as pets in home aquariums.
Scyphozoa have a complex life cycle that includes both a medusa (adult) stage and a polyp stage. The medusa is the more recognizable form, while the polyp stage is sessile and often attached to substrates in the ocean. During their life cycle, they undergo a fascinating process called strobilation, where the polyp forms a stack of disk-like segments that eventually bud off to become new medusae.
While they are not commonly kept in home aquariums, true jellyfish play a crucial role in marine ecosystems as both predators and prey. They help control plankton populations and serve as a food source for a variety of marine animals, including sea turtles and certain species of fish. For hobbyists interested in jellyfish, specialized jellyfish tanks are required to maintain the appropriate water flow and conditions needed to support their delicate structures and ensure their well-being.
