A Picture of Jellyfish

Jellyfish Facts

  • Name: Jellyfish
  • Subphylum: Medusozoa
  • Number of Jellyfish Species: 2,000+
  • Range: Worldwide (marine and freshwater)
  • Diet: Carnivorous
  • Size: Between .04 inches and 6.6 feet

20 Jellyfish Facts for Kids

  1. There are over two thousand species of jellyfish around the world.
  2. Jellyfish are estimated to be older than the first dinosaur.
  3. Jellyfish are invertebrates, which means they aren’t fish.
  4. Jellyfish can be clear (translucent) or have a vibrant array of one or more colors.
  5. Some jellyfish are bioluminescent, which means they can produce their own light.
  6. Jellyfish can be as small as .04 inches and as big as 6.6 feet.
  7. Jellyfish don’t have a brain, bones, eyes or a heart.
  8. A jellyfish’s body is 95% water. The other 5% is structural proteins, muscles, and nerve cells and structural proteins.
  9. Jellyfish are marine (saltwater) animals, but a few can tolerate or be found in freshwater.
  10. Jellyfish are carnivorous and eat crabs, fish, shrimp, tiny plants and other marine based animals.
  11. Jellyfish use their tentacles to stun or paralyze prey prior to eating it.
  12. A jellyfish uses its mouth to eat food, discard waste and squirt out water to propel itself.
  13. A group of jellyfish can be referred to as a bloom, smack or swarm.
  14. Groups of jellyfish can contain over 100,000 of them.
  15. The immortal jellyfish (Turritopsis dohrnii) is estimated to be immortal and have an infinite lifespan.
  16. Jellyfish pose a great danger to humans. They don’t purposefully attack humans, usually it’s by accident when someone swims near one or touches it on accident.
  17. A sting from a jellyfish’s tentacle can result in massive amounts of pain, scarring and even cause death.
  18. The Chironex fleckeri, also called the sea wasp, is one of the most lethal jellyfish to humans
  19. The box jellyfish, a group of 51 known species, is estimated to be the most venomous marine animal on our planet.
  20. It’s a myth that urinating on a jellyfish sting will relieve the pain. One way to alleviate the pain from a sting is to remove the tentacles with tweezers and soak the area stung in hot water.

Additional Resources on Jellyfish