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Fun facts about jellyfish (who aren’t even fish at all)!

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Fun facts about jellyfish - did you know they aren’t even fish at all?

  • Jellyfish evolution predates true fish by at least 100 million years. 
  • There are at least 1,500 different species of jellyfish.
  • Their numbers are expanding even as ocean waters warm and become more polluted.
  • Not all jellyfish can sting humans, but a few, like the box jelly, are lethally poisonous. 
  • A group of jellyfish is called a swarm or a bloom. Large blooms may contain millions of jellyfish and cover 10 square miles! 

Now, some of our favorite types of jellies!

Lions Mane:

This is the largest known species, with tentacles as long as 100 feet.


Though it looks like one, it is not a jellyfish but a siphonophore, an organism made up of many highly specialized, minute individuals called zooids.

Moon Jellyfish:

They tend to stay close to the surface of the water, making them easy prey for large fish, turtles, and the occasional marine bird.

Atlantic Sea Nettle:

Unlike other species of jellyfish that only eat plankton, sea nettles prey on minnows, worms, and mosquito larvae by stinging them with their powerful venom.

Immortal Jellyfish:

One Mediterranean species of jelly, the immortal turritopsis dohrnii, can return to its immature stage again and again after reproducing, meaning it may be able to live forever!

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