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Moon Jellyfish: Care Guide, Varieties, Lifespan & More (With Pictures)

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By Lindsey Stanton

Moon Jellyfish close up

Relatively easy to keep, Moon Jellyfish (Aurelia aurita) are the most popular kept jellyfish species. They are prevalent due to the relaxing movements they make and their white translucent color. In addition, moon jellyfish are less poisonous, making them less harmful to handle and ideal for keeping as pets in an aquarium.

Here is a detailed guide for you on how to keep and take care of Moon Jellyfish. Hopefully, you will feel confident adding these exotic pets to your aquarium at the end of the article.

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Quick Facts About Moon Jellyfish

Species Name Aurelia aurita
Family Ulmaridae
Care Level Between 8-8.4
Temperature 18-24 °C
Temperament They have short fringe-shaped tentacles, and the bell edge is a ring with this fringe
Color Form Translucent white
Lifespan Up to 1 year
Size 30cm (12 inches)
Diet Baby Brine Shrimp Cubic Medusa Jellyfish food
Minimum Tank Size Depending on the number of moon jellyfish
Tank Set-Up Rectangular/circular
Compatibility None, only with the same moon jellyfish species

Moon Jellyfish Overview

moon jellyfish
Image Credit: Peter Gudella, Shutterstock

The name Moon Jelly refers to any of the jellyfish in the genus Aurelia. They are round with a superficial bell and a relatively short limb. Like other jellies, the tentacles of a Moon Jelly are covered with special caustic cells, known as cnidocytes.

The creatures use these sharp, caustic cells for fishing tiny pelagic invertebrates and occasionally hunting to catch other food particles they might encounter. Although Moon Jellyfish inhabits the epipelagic area, you can commonly find them near the coast or in flooded zones.

These species are not very good swimmers, so you can often get them on beaches after strong tides or storms that force them onshore. Moon Jellyfish are the favorite prey of different open ocean predators, such as the leatherback turtle and the ocean sunfish.

However, they have shallow nutritional value. That means the predators that feed on them must consume hundreds of these jellyfish to maintain their needed energy levels.

Like most jellyfish, Moon Jellyfish undergo an interesting life cycle that involves a combination of sexual and unisexual reproduction. Adult Moon Jellyfish are often found around an open ocean.

How Much Do Moon Jellyfish Cost?

moon jelly fish close up
Image Credit: Piqsels

On average, a pet Moon Jellyfish can cost anywhere between $25 to $150, depending on the size. A tiny Moon Jellyfish costs around $30 to $60, while an adult Moon Jellyfish can cost up to $55 or $75. A starter kit that includes food and a pair of Moon Jellyfish can retail for anywhere between $150 to $400.

Typical Behavior & Temperament

Moon Jellyfish often swim horizontally, maintaining the bell closer to the surface. They keep the top of the bell approximately level with the ground, such that their tentacles point downward. That allows the bottom of its bell to cover as much underwater section as possible, allowing it fish food better.

Moon Jellyfish are carnivores, though their foods are incredibly tiny. They mainly feed on zooplankton, which are microscopic animals. Furthermore, they can eat small crabs, eggs, or any other small animals that they can catch.

Appearance & Varieties

moon jellyfish
Image Credit: Piqsels

Moon Jellyfish are known for their attractive appearance.

A mature Moon Jellyfish can grow up to 40 cm or 16 inches in diameter. It carries a bell-shaped medusoid body, and from the dish-shaped bottom hangs a short duct at the edge, which is its mouth. Bells of immature and young adults are translucent, but with maturity, they turn milky white, sometimes with a purple, blue, peach, or pink tint.

The tube’s edges form four fancy projections referred to as the mouth, arms, or oral. You can identify these species from their four-characteristic u-shaped gonads. Like other scyphozoan jellyfish, the Moon Jellyfish undergoes a hidden attached polyp phase before engaging its adult free-swimming form.

A Moon Jellyfish don’t have digestive, circulatory, or respiratory systems. They digest food through the help of the gastrodermis that borders the gastrovascular cavity, where nutrients are absorbed from food.

Aurelia labiata are a species of Moon Jellyfish and can be grouped into three geographical morphotypes. The southernmost found in California has a manubrium that is a broad circular frill. The spline canals vary in number, depending on age. The oral arms are usually straight.

Planulae differ in color from bright orange to white, and the bells are colorless or milky white. Male gonads are dark purple, while female gonads are pale pink. Southern Moon Jellyfish grow to approximately 35 cm.

The central species lives in coastal waters, including Santa Barbara, California, and Newport, Oregon. Plentiful in late summer, central moon jellyfish carry a narrow, rectangular, and elongated manubrium. They have numerous radial canals and straight or bent oral arms.

The planulae are violet, and medusae found in Monterey, California, are commonly purple, while those in Santa Barbara are usually pale pink. Male gonads are dark purple, while female gonads are brown. Central A. labiata grows to a maximum of 45 cm.

The Northern species carry a cup-shaped manubrium. They originate from lavender, Washington, and Prince William Sound, Alaska. The adults’ multiple radial parallel canals give it bell a fancy look. The oral arms are often straight, and the planulae are of different colors.

The bells are whitish or peach. Male gonads are dark purple, while female gonads are pale brown. Northern moon jellyfish vary in size from 14 to 29 cm.

How to Take Care of Moon Jellyfish

moon jellyfish in dark background
Image Credit: Piqsels

You cannot rear Moon Jellyfish in an ordinary square-shaped container that you find in most pet houses or stores. That is because jellyfish can harm themselves in a contemporary tank due to their sharp edges. Furthermore, the creatures might get trapped.

Always keep in mind that jellyfish have very delicate skin that can get damaged very easily. The best choice is to purchase a specially designed cylindrical tank.

Tank Size

The size of the tank depends on the number of Moon Jellyfish you want to keep. Moon Jellyfish come in different sizes where a young one is about 2-3 cm in diameter, while the largest adults size up to 15cm.

Water Quality & Conditions

Your tank should always be within the correct water quality parameters. Ensure you do a water quality test every few days after adding the Moon Jellyfish into your tank. However, once the tank has rested, you can conduct a water quality test weekly.

hand holding PH test
Image Credit: M-Production, Shutterstock

Moon Jellyfish can be stressed out if freshly added water isn’t stable. Therefore, always make sure you buy ready-made saltwater refills or use jelly salt with reverse-osmosis purified water.

Substrate

Moon Jellyfish are highly sensitive to changes in temperatures, pH levels, and salinity. So, always ensure you keep them in a stable environment, especially when cleaning the tank.

Plants

Plants play a crucial part in your aquarium. They provide shelter for your jellyfish and a place for them to breed and take care of their young ones.

Here are some of the best aquarium plants:

  • Hornwort
  • Moneywort
  • Hygrophilia polysperma
  • Amazon sword
moon jelyfish underwater
Image Credit: Damsea, Shutterstock

Lighting

Moon Jellyfish don’t have the brain or eyes to identify or see the light. A jelly can only know the difference between dark and light through a tiny organ known as rhopalia found around the jellyfish bell.

Investing in light will make your Moon Jellyfish and tank appear much prettier. Still, when you use these lights, you may overcome a few issues.

Like most aquatic animals, the problem is that most of these species’ internal functions depend on the daily light cycles. That means you must replicate these dark and light processes with your tank lights, essential for your jellyfish health. The recommended dark and sunlight hours are 12/12.

Filtration

It is always important to use filters and air pumps in your tank. That is because the water in the tank can get foul quickly.

Using a filter to dispose of the waste while using an air pump is essential because Moon Jellyfish usually flow with the water current and don’t swim. You must replicate the draft in your tank for the jellyfish to drift gently towards their food.

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Are Moon Jellyfish Good Tank Mates?

moon jellyfish with fish and coral
Image Credit: Damsea, Shutterstock

After arriving at your aquarium, you must gradually introduce your Moon Jellyfish to their new home since water parameters in the shipping bag might be different from those inside your tank.

Please don’t rush the acclimation process since it can shock your jellyfish and possibly harm them.

Once you arrive, open your box, and remove the bag containing the Moon Jellyfish. Place this bag near the aquarium and let it rest for 1-2 hours. That will allow the water in the bag to adjust to room temperature before proceeding slowly.

After this time has passed, you can continue with introducing your moon jelly to their new home.

In a few cases, you can keep Moon Jellyfish together with fish. However, you should entirely cycle the jellyfish tank and correctly establish it before adding some fish. Moon Jellyfish predators include ocean sunfish, egg jellyfish, and hydrozoan jellyfish.

What To Feed Your Moon Jellyfish

Like other jellyfish, Moon Jellyfish primarily feed on tiny animals like brine shrimp, krill, phytoplankton, and pelagic copepods. Still, you can provide them a mixture of any of these, though most people prefer finely chopped seafood.

For easy feeding, you can blend any or all these things into a paste and use a tubing or feeding needle to pour the food mixture into the water. But keep in mind that these creatures are specifically carnivores, so you don’t need to feed them any vegetables.

The best way to get started is to get a half teaspoon of food and pour it into the water near the Moon Jellyfish. That will encourage the tentacles to drift and catch the food.

brine shrimp
Image Credit: Dan Olsen, Shutterstock

Keeping Your Moon Jellyfish Healthy

Caring for your Moon Jellyfish can be the most challenging phase since these creatures are very delicate and can get damaged easily. However, it becomes easy to keep these creatures healthy when you understand what your tank needs to be like.

  • Salinity: The salinity of the water is one of the most crucial things when it comes to keeping your moon jellyfish alive and healthy. Moon Jellyfish are purely saltwater animals. Therefore, the first thing you need to do is find a saltwater testing kit to help you measure the water salinity. The salinity in your jellyfish tank must be between 32-35 ppt.
  • pH Level: pH level is another crucial aspect that you need to consider keeping your jellyfish healthy. Moon Jellyfish require a pH level between 8-8.4, which is extremely basic. That means they don’t love acidic water, so they can’t survive in it. To maintain the pH within the given parameters, make sure you get a pH testing kit.
  • Nitrite, Nitrate, & Ammonia: Jellyfish are very sensitive towards ammonia, nitrate, and nitrite compounds. But to keep your Moon Jellyfish healthy, all these compounds should be at a 0.0 level parts per million in water.
moon jellyfish
Image Credit: Dan_Manila, Shutterstock

Breeding

Moon Jellyfish breeding often doesn’t have a defined time frame, and they breed a whole year around. Moon Jelly reproduction occurs when medusa becomes sexually mature, typically occurring in the summer and autumn months for 2 to 3 months.

Unlike other species, Moon Jelly breeding requires effort, patience, and proper installation and techniques.

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Are Moon Jellyfish Suitable for Your Aquarium?

Moon Jellyfish are very fantastic creatures to keep in your aquarium. These animals are relatively simple to take care of, provided you keep the water at the optimal parameters and feed them properly. Keeping Moon Jellyfish is also an excellent source for acquiring knowledge and furthering your understanding of them.

Although Moon Jellyfish aquariums are available for purchase in the local stores, creating and installing your own system can be an exciting project. Every system is unique, and you should design it according to specific space, size, feeding, filtration, and care needs. The size of an aquarium will help you determine the number of moon jellyfish to keep, and the amount of filtration required.


Featured Image Credit: Richard A McMillin, Shutterstock

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