How Long Are Jellyfish Alive For? (Jellyfish Lifespan)

| Published On: is supported by its audience. When you buy through links on our site, we may earn an affiliate commission. Learn More
What Is The Average Jellyfish Life Cycle

The aquatic creatures known as jellyfish, which have stinging tentacles, are really in the middle of their life cycle. People of all ages are amazed when a jellyfish swim about in a tank.

They are both incredibly frightening due to how painful their stings may be and absolutely interesting due to their appearance.

The jellyfish is cloaked in a great deal of mystery. Especially when it comes to knowing how long jellyfish live and their lifespan of jellyfish.

The answer to these questions is, of course, that jellyfish have a variety of lifespans depending on the species. Other elements include whether they are kept in captivity or live free in the wild.

Due to the incredible diversity of jellyfish, I’ve chosen to walk you through their life cycle and lifetime. There is plenty to learn about this amazing animal, whether you are a jellyfish fanatic wishing to keep one as a pet or just a casual admirer.

How Long Do Jellyfish Live?

The type of jellyfish can live anywhere from a few hours to several months or even years. Jellyfish typically have a lifespan of one to three years.

image of some jellyfishes

However, some species only have a short lifespan, while others can live for several decades. Due to the complexity of jellyfish’s life cycles, scientists cannot tell how long jellyfish live.

  • The moon jellyfish, or Aurelia aurita, one of the most well-known jellyfish, is believed to have a lifespan of 12 to 18 months but, under ideal conditions, can live up to 20 years.
  • The Flame Jellyfish or Rhopilema esculentum, which can only live for three months to a year, has a fairly short lifespan.
  • The Cannonball jellyfish, or Stomolophus Meleagris, another well-known jellyfish, may survive in the wild for three to six months and can survive for many months longer when kept in captivity.
  • The Lion’s Mane Jellyfish or Cyanea capillata, the most beautiful and possibly biggest, lives an average of one year.

According to research, the huge quantities of pluripotent stem cells that underlie these creatures’ exceptional capacities for self-regeneration and rejuvenation are fundamental factors in the lifespan and immortality of most of these simple species.

Cells that can self-renew by dividing are called pluripotent stem cells. As a result, the immortal jellyfish can live forever!

More articles related to this one:

What Is The Average Jellyfish Life Cycle?

Are you curious about the jellyfish life cycle’s appearance? What to anticipate if you opt to keep a pet jellyfish is listed below!


Eggs are the first stage in the jellyfish life cycle. Jellyfish sexually reproduce. With gonads, which are the reproductive organs, mature jellyfish can be either male or female.

Jellyfish species fertilize their eggs in various ways, but all involve male and female jellyfish. Some male jellyfish will expel sperm through the mouth hole on the underside of their bell. The female then swims across the sperm to fertilize the eggs.


The eggs of the female jellyfish soon start to hatch after being fertilized by the sperm of the male. The planula larvae will then crawl out of the mouth or brood pouch of the female jellyfish.

The planula larva floats on the water’s surface for a few days. The planula larva will start to develop into a polyp if any predators don’t consume it.


On the seafloor, the planula larva will start to settle and become a polyp. Around this point, the jellyfish polyp will remarkably resemble coral. The polyp’s digestive system is fully formed at this point.

This enables it to gather prey and adequately nourish itself. The polyp will keep expanding until it eventually breaks out and starts living independently.


A jellyfish goes through an ephyra stage before becoming an adult. Unlike a fully matured jellyfish, the ephyrae lack a closed bell form and stinging tentacles. It must rely on the underdeveloped lobes of its bell to push food toward its mouth.


The ephyra begins to resemble a jellyfish as it ages and develops into that shape. Its tentacles and oral arms expand, and it starts to take the shape of a bell.

This last stage is referred to as a medusa. This new adult is a mature mammal capable of reproduction despite its small size.

How To Extend The Life Of Your Pet Jellyfish?

  • Feed live or frozen young brine shrimp to the jellyfish twice daily. It is advised to feed your jellies twice a day—once in the morning and once at night.
  • For up to two weeks, live shrimp brine can be kept in the fridge. You can feed the jellyfish through a small opening in the tank to prevent getting stung by their tentacles. The jellyfish should capture and eat the food on their own.
  • If you overfeed your jellies, your tank’s water quality may suffer. If your aquarium contains both smaller and larger jellyfish, you might not be able to encourage the smaller jellyfish to grow and maintain their health by overfeeding them.
  • Once per week, replace 10% of the aquarium’s water. To maintain good water quality, execute a daily 10% water change in your tank. This means that new salt water will be added to replace 10% of the water.
  • Make sure to check the water’s purity after each water change. The ideal salinity range, which is equivalent to natural seawater, is 34–55 ppt. Additionally, ensure the tank’s ammonia, nitrite, and nitrate levels are appropriate. The tank’s temperature should be between 18 and 25 C.
  • Remove any jellyfish that have gotten too big for the aquarium. With the right care, your jellyfish should be able to grow to a healthy size. To minimize overcrowding, just maintain a few jellyfish at a time in your tank.
  • To find a new home or carer, you should speak with the merchant from whom you bought the jellyfish.

Who Discovered Immortal Jellyfish?

In 1883, researchers published the first description of the species T. dohrnii. The 80s, 100 years later, saw the unintentional discovery of their immortality.

Giorgio Bavestrello and Christian Sommer collected Turritopsis polyps and kept track of them until medusae emerged.

image of Immortal Jellyfish

When the jar was checked the next time, they were shocked to see many newly settled polyps. It was assumed that these jellyfish would need to develop before spawning and producing larvae.

When the medusae were under stress, they would drop to the bottom of the jar and develop into polyps without fertilization or the regular larval stage taking place, according to their continuing observations of the jellyfish. The world was drawn to the finding due to the unique moniker immortal jellyfish.

Where Are Immortal Jellyfish Found?

More species that are identical to the immortal jellyfish have been discovered since its discovery in the Mediterranean Sea, including in Japan, Spain, Panama, and even the Atlantic Ocean side of Panama.

They get caught in ballast waters from long-distance ocean cargo ships, which is why they are dispersed so far.

image of The Immortal Jellyfish In Ocean

Despite the genetic similarity of most species, each one has developed a unique physical adaption to fit its environment. For instance, tropical examples have eight tentacles, whereas those from more temperate places have twenty-four.

Final Verdict:

The jellyfish is one of the very few creatures that doesn’t appear to have been harmed by climate change and human meddling. According to scientists, jellyfish populations have grown during the past few decades.

Freshwater jellyfish is one kind of endangered jellyfish. This tiny, native jellyfish from China lives only in freshwater, not saltwater. Its population has been declining in China owing to water pollution.

The world is home to many freshwater sources, including lakes, reservoirs, and rivers. If you enjoy jellyfish, your search for the chance to own these amazing creatures as pets are over.

Thanks to the development of specialized circular aquariums, jellyfish can now be maintained as pets in your own home.

Pet jellyfish can live for many years if properly fed and cared for. What are you still holding out for? You can simply realize your desire to get a pet jellyfish!

Frequently Asked Questions

#1 – Can Jellyfish Live For 1000 Years?

The world’s oldest multi-organic mammal, the jellyfish, has been around for at least 500 million years. The 500 million-year-old jellyfish fossil is the oldest one of its kind.

Turritopsis nutricula, a jellyfish, is biologically immortal and has the potential to live for thousands of years in the right circumstances. This jellyfish can return to the immature polyp stage after sexual reproduction. Although the jellyfish can still perish from predation, it is unaffected by aging.

#2 – How Old Is The Oldest Jellyfish?

Using recently discovered fossil images found in rocks more than 500 million years old, scientists have identified the oldest unequivocal jellyfish yet discovered.

#3 – Do Jellyfishes Have Hearts?

Jellyfish are quite simple creatures because they lack brains, blood, or even hearts. They consist of three layers: the gastrodermis, which is the inner layer. Mesoglea is a thick, elastic layer in the middle, and the epidermis is the outside layer.

They don’t need lungs since their skin is so thin that they can absorb oxygen through it. They don’t need the heart to pump blood because they don’t have any.

#4 – How Old Is The Immortal Jellyfish?

There is a jellyfish that can live forever, according to scientists. The sole immortal creature is recognized as the Immortal Jellyfish, technically known as Turritopsis dohrnii. It turns out that the key to eternal life is not simply to live a very, very long period, possibly for all time.

What’s more amazing is that a single immortal jellyfish could have survived this entire time, given that these critters have been swimming in the oceans for much longer than the dinosaurs.

Your Author

  • Since 2009 I've been writing on different media portals about fishing. Here on this website, it's time to share those experiences I've witnessed in my entire life so far. Let me help you get the best stuff you need while fishing.