There are jellyfish in every ocean in the globe. Even some freshwater lakes and ponds contain them.¹⁾

Jellyfish have tentacles that can extend 200 feet and range in size from a thimble or the eraser tip of a pencil to around eight feet in diameter. That equates to two blue whales in length.²⁾

Thousands of cells known as cnidoblasts are embedded in each jellyfish tentacle. The nematocysts, which each contain a coiled stinging thread, are found inside the cnidoblasts.³⁾

The major defensive systems of the jellyfish are its stings and its translucent body, which makes it simple for it to conceal itself.⁴⁾

In a Friends episode, one of the characters treats a jellyfish sting with pee. Urine, according to neuroscientists, is ineffectual.⁵⁾

According to many neurosurgeons, common anti-sting therapies like vinegar, urine, and meat tenderizers are ineffective. The best course of action is to exit the water right away and wash the damaged area with salt water (NOT fresh water). The stinging cells will become inactive in salt water, but they will become active again in fresh or tap water. Utilizing a tool like a credit card is the most effective approach to remove the cells.⁶⁾

A jellyfish's body has a little tube that hangs downward. Its mouth and digestive tube are both contained within the tube.⁷⁾

There are no brains, hearts, ears, heads, feet, legs, or bones in jellyfish. ⁸⁾

They can breathe through their skin because it is so thin.⁹⁾

Although jellyfish lack a brain, they do have a basic neurological system that includes sensors for light, vibrations, and chemicals in the water.¹⁰⁾

The Jellyfish is able to navigate and orient itself in the water using gravity and its sense of weight.¹¹⁾

Invertebrates, or creatures without a skeleton, include jellyfish. Their body contains about 95% water.¹²⁾

Although jellyfish are often found in shallow coastal waters, several species have been found to exist at low depths.¹³⁾

Some jellyfish may survive in subarctic conditions, however most prefer warm water.¹⁴⁾

Even when detached from the jellyfish body, a tentacle can still sting.¹⁵⁾

The creeping jellyfish is the tiniest jellyfish in existence. It contains bell disks with diameters ranging from 0.5 mm to a few millimeters.¹⁶⁾

The very deadly Australian Irukandji jellyfish, which is just the size of a fingernail, is another contender for the title of tiniest jellyfish.¹⁷⁾

The Nomura's jellyfish is the biggest jellyfish in the world. The Lion's mane jellyfish and the Stygiomedusa gigantea are further contenders for the title of biggest jellyfish.¹⁸⁾

In the past 120 years, only around 100 times have the enormous jellyfish known as Stygiomedusa gigantea been observed.¹⁹⁾

Although the Portuguese man-of-war resembles a jellyfish, it is not one. It isn't even a single animal, really. It is a siphonophore, an animal made up of a group of coexisting creatures. The man-of-war is really made up of four different polyps. The top polyp is a gas-filled bladder that resembles the sails of the formerly popular man-of-war ship.²⁰⁾