Jellyfish Facts for Kids

Dive into the mysterious and graceful world of jellyfish, the floating wonders of the sea! Jellyfish are fascinating marine creatures known for their gelatinous bodies and gentle, pulsating movements in the water. With their translucent, often colorful bodies and trailing tentacles, they are like living works of art in the ocean. From the tiny irukandji to the enormous lion’s mane jellyfish, these creatures come in a stunning array of sizes and types. Perfect for young marine biologists and ocean enthusiasts, these 30 fun facts about jellyfish will take you on an underwater adventure to explore the captivating life of these unique sea dwellers. So, let’s set sail and discover the enchanting world of jellyfish!

30 Jellyfish Fun Facts for Kids

  1. Jellyfish have been around for over 500 million years, making them one of the oldest living creatures on Earth.
  2. They are not fish but invertebrates, animals without backbones.
  3. A group of jellyfish is called a ‘bloom’, ‘swarm’, or ‘smack’.
  4. Jellyfish are made up of about 95% water.
  5. They don’t have brains, hearts, bones, or eyes.
  6. Jellyfish use their tentacles to sting and capture prey.
  7. The sting of a jellyfish can be painful to humans and sometimes dangerous.
  8. Some species of jellyfish are bioluminescent, meaning they can produce their own light.
  9. The lion’s mane jellyfish is the largest known species, with tentacles that can extend up to 120 feet.
  10. Jellyfish are found in every ocean, from the surface to the deep sea.
  11. Baby jellyfish are called ‘ephyrae’.
  12. Jellyfish have a simple digestive cavity for both ingestion and excretion.
  13. Some jellyfish can clone themselves, creating exact duplicates.
  14. Jellyfish don’t have a respiratory system; they absorb oxygen directly through their skin.
  15. The box jellyfish is considered one of the most venomous marine animals.
  16. Jellyfish movement is largely dependent on ocean currents, tides, and wind.
  17. They have a basic sensory nerve net but no central nervous system.
  18. The immortal jellyfish (Turritopsis dohrnii) can revert to its juvenile form after becoming sexually mature.
  19. Jellyfish diets consist mainly of plankton, small fish, and other jellyfish.
  20. The lifespan of a jellyfish varies greatly; some live only a few hours, while others can live for several years.
  21. Jellyfish can range in size from about one millimeter to over two meters in diameter.
  22. They have radial symmetry, meaning their body parts radiate from a central point.
  23. Some jellyfish species have been known to swarm power stations and clog cooling pipes.
  24. Despite their name, jellyfish are not related to fish.
  25. Jellyfish tentacles can still sting even if they are detached from the jellyfish’s body.
  26. The cannonball jellyfish is often used in Asian cuisines.
  27. Jellyfish populations are increasing in some parts of the world, a phenomenon known as a jellyfish bloom.
  28. They play an important role in the oceanic food chain.
  29. The moon jellyfish is one of the most common and widely recognized jellyfish species.
  30. Jellyfish have inspired designs in art, literature, and even technology.


Q: How do jellyfish sting?
A: Jellyfish sting using tentacles covered with tiny, venom-filled cells called nematocysts. When triggered, these cells launch a harpoon-like structure that injects venom into the target.

Q: Can jellyfish be kept in aquariums?
A: Yes, some types of jellyfish can be kept in specially designed aquariums that ensure continuous water flow as they cannot swim against currents.

Q: What do jellyfish eat?
A: Jellyfish typically eat small fish, shrimp, crab, tiny plants, and plankton. They catch their prey using their tentacles.

Q: Are all jellyfish venomous?
A: Most jellyfish have some form of venom, but not all are harmful to humans. The degree of venom varies significantly among different species.

Q: Do jellyfish have any natural predators?
A: Yes, jellyfish have natural predators like sea turtles, some species of fish, and even other jellyfish.

Discovering the world of jellyfish reveals the diversity and wonder of marine life. Each fact about these ethereal creatures highlights the importance of understanding and respecting the ocean and its inhabitants.