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Moon Jellyfish Care Guide | Everything To Know | Exotic Pets

Moon jellyfish have a beautiful appearance and are fully transparent species, where some younger ones will carry patterns of spots and a faint purple hue.

Moreover, moon jellyfish are less venomous, making them less dangerous to handle, making them ideal for keeping them in captivity [ tanks] as exotic pets.

In this article, I’ll answer all your questions regarding Moon jellyfish. Hopefully, by the end of the article, you’ll feel confident adding these exotic pets to your collocation.


Moon Jellyfish Facts

  • Lifespan: Captive -11 to 12 months | Wild – 2 years
  • Sting: None
  • Water Temperature: 18-24°C
  • Food: Baby Brine Shrimp, Frozen Brine Shrimp, and finely chopped seafood.
  • Maximum Size: 25-40 cm or 10 – 16 inches in diameter
  • Compatible with None, only with the same Moon jellyfish species 

Can you keep Moon Jellyfish as pets?

If anyone asks whether they can keep a jellyfish as a pet, the answer is yes only if you can create and maintain the appropriate environment for them. So, these are fascinating marine animals to keep as pets for such a primary life form.

The moon jellyfish is a spineless aquatic animal. That has no eyes and brain; the nearest relatives to a jellyfish are planktons or corals.

Get to know them.

natural Habitat

Moon jellyfish, also known as Aurelia Aurita, is a genus of scyphozoan jellyfish. You can see these Aurelia Aurita commonly in the Atlantic Ocean, Arctic Ocean, Pacific Ocean.

You can see them in the waters of Northern China, Japan, Korea, Australia, New Zealand, Black Sea, Off California, Indonesia, the eastern coast of the United States, and Europe.

Best locations to see these types of moon Jellyfish are in Europe and off the coast of California,

Appearance And Size

The moon jellyfish are known for their beautiful appearance. Also called saucer jellyfish, Aurelia Aurita is almost entirely translucent.

Usually about 25-40 cm or 10 – 16 inches in diameter, you can identify these species from their four-characteristic horseshoe-shaped gonads.

Younger moon Jellyfish usually carry patterns of spots and streaks along with a faint purple hue. These invertebrate aquatic animals are bioluminescent (glow in the dark).

Tip: Moon Jellyfish are 95% water and have no brain, blood, or heart; feeding is a biological process.

Moon Jellyfish feeding

How Long Do Moon Jellyfish Live

Moon jellyfish life depends on which stage of life it is in. in an aquarium setting, Polyps have lived approximately 2 years. But a mature moon jellyfish that is producing does not live long. In the wild maximum reported age is 2 years.

After the jelly has done its part sexually, which ensures the survival of its species, the transparent body of the moon jellyfish starts to become non-transparent and loses its lightness, eventually dying limiting lifespan11 to 12 months.

Also lifespan is directly depend on environmental conditions water temperature and water quality

Growth Rate

Jellyfish are harmful species that have vast numbers of populations around the world. Research has shown a rapid increase in their numbers for the past years.

Experts advise that this is due to the low numbers of different types of predators in those areas. Also, faster growth can be seen during spring.

Food Preference

Moon Jellyfish have a wide variety of food preferences, and there are many creatures that they Feed. For example, some of the Jellyfish food includes,

  • Medusa
  • Plankton
  • Mollusks
  • Crustaceans
  • Tunicate Larvae

And other tiny organisms.

Also Read: What Does Moon Jellyfish Eat? How To Feed Them In Aquarium

The behavior of Moon jellyfish 

Moon jellyfish commonly swims horizontally, always keeping the bell closer to the surface. All the time, they can spread their tentacles over a large area basically to catch food better.

Aurelia Aurita has a minimal motion where it drifts typically with the current even while swimming.

Are They Toxic? 

Jellyfish are known for their fearsome stinging ability to use their tentacles to force toxic into their prey,

But, the moon jellyfish significantly less toxic for humans. Though a signal sting from one jellyfish is relatively not harmful. But, a larger group of jellyfish called a bloom or smack could be toxic and dangerous. Mostly a string might Cause you mild itchiness.

Moon jellyfish are known for their fearsome stinging ability to use their tentacles to force toxic into their prey

One Look Care Guide

Scientific nameAurelia aurita
Common nameMoon Jellyfish
Care levelBetween 8-8.4
Native toAtlantic Ocean,
Arctic Ocean,
Pacific Ocean,
Commonly in Northern China,
New Zealand,
Black Sea,
Off California,
Eastern coast of the United States,
TypeAquatic Animal
ColorTranslucent White
Tank sizeDepending on the number of moon jellyfish
Preferred temperature18-24°C
Other water parameters (ammonia, etc.)Ammonia – 0.0 ppm
Nitrite < 0.05 ppm
Nitrate < 10.0 ppm
Preferred salinitySalinity levels 32 to 33ppt.
Size of the moon jellyUsually about 25-40 cm
10 – 16 inches in diameter.
Growth rateDouble in the past few years due to the decrease of predators
TemperamentThey have short fringe-like tentacles instead of long dangling ones, and the edge of the bell is a ring with this fringe.
Recommended tank matesNon
Preferred foodBaby Brine Shrimp,
Frozen Brine Shrimp,
Finely chopped seafood.
Feeding frequencyYou can see the food right through their skin best is to feed them two times a day.
BreedingMoon jellyfish have a life cycle that includes both sexual and asexual reproduction.
Some jellyfish can have as many as 45,000 eggs in a single night.

Moon jellyfish care in Aquariums

Moon jellyfish are commonly used aquatic animals as pets, mainly for their transparent body and relaxing movements.

Aquarium care includes various things, including the Jellyfish environment, the tank, nutrients provided, water temperature, etc. 

Moon Jellyfish TANK

Moon Jellyfish Tanks

You cannot raise moon jellyfish in a regular square-shaped tank that you find in every pet store or house. Therefore, jellyfish can damage themselves in a traditional tank due to their right-angle corners; the creatures might get trapped.

Always remember jellyfish have very delicate skin that will get damaged very quickly. Buying specially designed cylindrically shaped tanks is the best choice.

Preferable Size

The number of moon jellyfish in one tank depends purely on the size of the tank you have. This is because jellyfish come in different sizes where the small young, once 2-3cm in diameter, and the more enormous adults sizing up to 15cm.


Jellyfish are highly sensitive to changes in salinity, pH levels, and temperatures. Therefore, always remember to keep them in a stable environment, mainly while cleaning the tank.

Do They Need Filters and Air Pump?

Yes, You must always use filters and air pumps since it is a tank, and the water would get foul quickly. It is wise to use a filter to dispose of the waste, and using an air pump is essential since moon jellyfish usually drift with the ocean current and do not swim.

We have to replicate the draft in the tank for the jellies to drift gently towards the food.

Lighting for Aquarium

Moon jellyfish do not have eyes or a brain to see or identify the light. The only way a jelly can recognize the difference between light and dark is through a small organ called rhopalia situated around the bell of the jellyfish.

Using a light will make your tank and moon jellyfish look much prettier. Still, when using these lights, you might overcome these few issues.

Like many aquatic animals, the other issue is that some of these species’ internal functions depend on the daily light cycles.

Therefore, you must replicate these light and dark processes with your tank lights, which is highly important for your jellyfish health. Recommended light and dark hours are 12 to 12.

Best aquariums for moon jellyfish (commercial aquariums)

jellyfish have very delicate skin, and since they float in the water, the chances of getting trapped in the corners of a rectangle tank are very high. Therefore, the best tank for the moon jellyfish are cylindrically shaped tanks.

Where to place the tank

When thinking of placing your jellyfish tank, you must keep few things in mind, which is as mentioned below,

  • Must not keep the tank near any windows or in the path of direct sunlight.
  • Must have independent power sockets to power the tank freely.
  • Always place the tank on a level surface. 
  • Make sure power outages do not affect the process of the tank.

How many Moon jellyfish should be kept together per gallon?

You are advised to keep one inch of bell diameter per gallon. So, for example, if you have a five-gallon tank, you can put three 2-inch diameter jellyfish.

Water quality condition

To ensure that the recommended water quality parameters correctly maintained.

You must conduct a water quality test every few days after adding the moon jellyfish into the tank. Once the tank has settled down, you can do a water quality test every week.

Water Quality Parameters

pH level must be within 7.9 and 8.4, and the salinity must be between 34 to 35ppt [ natural seawater].

Must change 20% of the tank’s water weekly, but the frequency of this process depends on how many moon jellyfish you have in the tank.

Moon jellyfish can be stressed out if the newly added saltwater is not stable, so always recommend purchasing saltwater refills that are pre-prepared or using jelly salt with reverse-osmosis filtered water.

How To Direct If Water Quality Is Bad

Always keep in mind if the moon jellyfish are shrinking down in size when water quality is not optimum.

Also, you feel that your jellyfish is not growing, the reason is simply because of poor water quality in your tank. Jellyfish are susceptible species and will not feed if the water conditions are poor.

Do Not Use Tap Water

Tap water usually has small amounts of minerals and metals. Humans hardly notice this when drinking; even though these are minimal concentrations, these metals and minerals can seriously damage the moon jellyfish’s body functions.

That is what you must always keep in mind when changing the water in the tank to use salt mixed water or reverse -osmosis filtered water and never use water from the tap.

Use Filtered Water

Always use reverse-osmosis filtered water or distilled when adding fresh water to the tank. Ensure that the label says only distilled and not spring water, purified water, mineral water, alkaline water, or anything else.


The temperature must be between 18 to 25 degrees, and Normally it will be a couple of degrees below the room temperature.

Salinity (Do Not Use Salt Crystals to Increase Salinity)

Jellyfish grow better when the salinity levels are between 32 to 33ppt. It is ok if the salinity levels go a bit below the mark, and always remember not to change the salinity levels frequently.

Do it gradually over a few days. Ensure that you will not add any RO or distilled water directly to the filter box to destroy the good bacteria.

Always keep in mind undissolved salt can give incorrect readings and might be an issue for the moon jellyfish since these species are susceptible to salinity changes. High salinity levels can also delay their movement, eating, and overall activity.


Amendments to other water parameters are very rare, and you must avoid using any chemicals which could upset moon jellyfish in the long run.

Figures to aim for are as follows:

  • pH: 8.1 – 8.4
  • Ammonia = 0.0 ppm
  • Nitrite < 0.05 ppm
  • Nitrate< 10.0 ppm
  • Phosphate< 2.0 ppm
  • Alkalinity 7.4 – 8.4 DkH

Ammonia, Nitrite and Nitrate

It is normal to see your tank transforming cloudy, which is caused by beneficial bactiria.

For example, nitrifying bacteria that break down ammonia (NH3) and nitrites [NO2] into nitrates [No3] over time and will multiply.

Although nitrifying bacteria typically reproduce slowly, it takes around 15 to 20 hours to double the population.

Moon Jellyfish can survive for several months with elevated levels of Ammonia, Nitrite, and Nitrate. But, it will result in shortening tentacles, weaker pulsing, a flatter bell, and eventually death.


Always remember that the pH level must be within 7.9 and 8.4. If the correct level is not maintained, it will harm the moon jellyfish’s overall activity and affect its growth.

Water changing 

You should perform a 20% water change every week depending on how many Moon Jellyfish you have in your tank. The fish detritus and other waste products cause the water to increase ammonia, Nitrite, nitrate levels and decreased pH level.

As Moon Jellyfish are sensitive fish species, the water condition should be at ideal levels at all times to keep them healthy.

We discourage extensive water changes because good bacteria may die if you change a large amount of water. This may cause your Jellyfish to hurt and shred due to stress and may eventually die.

Health Of the Moon Jellyfish

Caring for your moon jellyfish is the most challenging part since these species are highly delicate and can get easily damaged. Knowing why your jellyfish is unhealthy and why and what precautions must you take.

Different Ways They Can Get Hurt

Few ways how your moon jellyfish might get hurt is.

  • The possibility of getting your jellyfish suck into the pump
  • Using a standard square tank will also damage your moon jellyfish and become trapped in the corners of the tank.

Moon Jellyfish Upside Down

A common reason why this occurs is because of malnutrition that will make your Jellyfish flip due to weakness. It happens when your jellyfish are not eating correctly.

Then they can shrink in size and eventually die. To solve this you can separate that jellyfish into a small container and feed them separately using a dropper.

When that jellyfish are fed well you can see the food inside of them. After that, you can add them to your tank. But, when you take them out of the tank take care not to expose them to air.

Diseases of moon jellyfish

Tentacle Balls – Unhealthy

Jellyfish tentacles get tangled and knotted around the perimeter of the bell.

The cause for this disease is the lack of flow in your tank. Moon jellyfish tentacles will become tangled if there is not enough support from the current water flow to support their movements (swimming). Once you fix this issue, this condition will reverse itself.

Bell Eversion – Unhealthy

In this case, the bell flips up, and over the top of the bell, the Jellyfish creates a saucer or cup-like look. Unlike a healthy Jellyfish, oral arms are hanging down and not tucked up under the bell.

There are several causes for this condition. The first one is malnutrition. It can also occur when the flow rate is too high or too low, leading to poor belling leading to eating problems.

If the Jellyfish gets physical damage, it can also cause them to invert their belling like a cup.

Flying Saucer Bells – Unhealthy

If your moon jellyfish are non-transparent and slow to bell, the radial canals are invisible and faded. Instead, you will see the bell curled under with the oral arms hanging down.

The cause for this issue is mainly improper acclimation. Unfortunately, this condition is permanent once it occurs.

Target feeding with acidic and concentrated foods on a regular and excessive basis can desensitize the Jellyfish and cause the perimeter to curl under and deform the oral arms.

In some cases, it can cause an arrhythmia, in which the Jellyfish bells in a circular pattern rather than normal.

Clear open bells – Healthy

If you can see your moon jellyfish bell-clear with defined radial cancels, that indicates that your jelly needs to fully metabolize food.

Always remember to provide your jellyfish with proper nutrition to keep the perimeter of the bell smooth and open, not rigid and curls.  

The simplest solution for this: Take at least 15 minutes to acclimate the jellies to the temperature of your tank and take another 45 minutes adapting them to your tank water chemistry using small water exchanges within the bag before releasing them. It will give your moon jellyfish the time it needs to adjust. 

Bell Erosion & Tears– Unhealthy

In this condition, you can see some erosion and tears in Jellyfish’s bell.

The cause of this condition is mainly toxic water. When the water is filled with Ammonia ad/or Nitrite, it will cause your Jellyfish’s bell to damage.

Another cause is physical damage. If a siphon tube, turkey baster, or scrub brush has come in contact with the Jellyfish, their bell may damage because of that equipment.

What fish can live with Moon jellyfish in aquariums?

None. You cannot put the moon jellyfish with other aquatic animals.

Moon jellyfish predators

Moon jellyfish have commonly been preyed on by Mola Mola, also known as ocean sunfish. Leatherback sea turtle, [phacellophora camtschatica] also known as fried egg jellyfish or egg york moon jellyfish, by crystal jelly, also known as hydrozoan jellyfish, and fed by sea birds.

Related Questions 

Are moon jellyfish easy to care for?

Jellyfish are well-known hard to care species. Due to their delicate body, even a slight change of temperature can kill them. 

Can you touch a jellyfish?

 It is still advised not to touch any jellyfish regardless of their low sting capabilities. 

Are Jellyfish legal to own?

And in most other countries, it is not allowed. But in California, USA, it is permitted.

Can Jellyfish be kept in an aquarium?

Yes, you can keep in mind that Jellyfish have a unique set of tanks designed for them. Using any one of those, you can keep them in an aquarium.

Related : Fairy Shrimp Vs. Brine Shrimp : Everything You Need To Know

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About Dr.Chamika

Hello, I'm Dr. Chamika. I am a Researcher in Water quality, Aquatic organisms, and Environmental chemistry. I am a passionate fish keeper, with10 years of experience. My mission is to help other aquarists experience the joy of fish keeping.