Moon Jellyfish Online


Sunset Marine Labs Policy for Live Jellyfish Sales

Understandably, we are concerned about the welfare of our animals.  Many people do not understand that a specialized tank with proper filtration is necessary to responsibly keep jellyfish as pets. Therefore, to guard against misinformed purchases of live animals online, we reserve the right to cancel any live jellyfish order at our discretion. 


Why call it "eon"?

Well, simply because they’ve been around that long---for eons---we decided to call our revolutionary personal jellyfish system just that, eon.  Respectful of the time they’ve been on the planet, we thought the name should depict their seniority in the animal kingdom.


What is a Tumbler tank?

In the mid 1990’s, Monterey Bay Aquarium and the Bellagio Casino in Las Vegas took an amazing step away from the tried-and-true plankton kreisel design, the one that incorporates what is termed as a laminar flow design, and ventured into the square-flow arena.  Typically, since the 1960’s plankton kreisels have a formed piece of acrylic secured inside of an acrylic tank. This circle or oval of acrylic is the framework that aids the incoming water to create a false current that keeps the jellyfish suspended.  The water is introduced into the kreisel area via spray bars that produce a thin layer of jetting water along the formed acrylic.  Hence, a laminar flow of water is created inside the exhibit.  A gentle, circular current is the result and the jellyfish remain in motion, in a repetitive circular motion.

The tumbler tank was a new way to experience jellyfish and it was a revolution in jellyfish exhibits.  Although it might resemble a regular square aquarium, there is a profound use of plumbing “puppetry” that makes a modified tumbler box—the original name for this type of jellyfish tank—function properly and safely for jellyfish.  The most wonderful aspect of the tumbler design is that the jellyfish experience a far more natural state of existence than with a plankton kreisel. The traditional kreisel keeps the jellies in a whirlpool of round and round and round---which they do not experience in nature. The tumbler tank offers a gentle up and down flow which stimulates belling and leads to proper feeding behavior which leads to a healthy and happy jellyfish.

We have been utilizing the square-flow design for several years and now we are excited to offer this same technology to you, the hobbyist and jellyfish enthusiast!  Watch the videos and see for yourself the natural beauty that comes from a jellyfish belling naturally and normally in a proper environment. 


How does shipping work?

Shipping Jellyfish: Overnight delivery is mandatory & you must be available to acclimate the jellyfish into your jellyfish aquarium the day they arrive.  We ship Standard Overnight delivery via FEDEX which puts the jellyfish on your doorstep in the afternoon. 


I have my own UPS or FedEx Account.  Will you use it to ship my order?

Sure thing!  Just indicate your account number in the NOTE TO SELLER during checkout.  


Why can’t you use tap water to make up your saltwater?

Heavy metals are present in tap water and will destroy your jellies.  You must use RO (reverse osmosis) or distilled water to make up your saltwater. The other option would be to purchase NSW (natural seawater) if it is available to you. 


Do we offer an “Arrive Alive” guarantee?

Of course our animals will arrive alive.  There is no reason they should arrive any other way.  We have been shipping jellies across the US and around the world from the Bahamas, to Spain, to Dubai.  We know how to pack them properly and we know how to ship them.  Our main concern is to help you keep them alive once you receive them. Please watch our Acclimation video, as that is crucial to their existence on your end.  If you don’t acclimate them according to our instructions, we cannot guarantee their survival. (Please note, we do not recommend the “drip” method as commonly used for fish.)  However, if for some reason UPS smashes your package and all is lost, of course we will reship your order.  This has yet to happen even one time in the past 19 years, but if it does, we have your back! If you receive your shipment and you feel there is a problem in some way, please notify us within 12 hours from the time of delivery so we can assess the situation. Any notifications after 12 hours are not guaranteed. Please read our Refund Policy.  Also, please note: We guarantee live arrival but cannot guarantee they will survive in an improper jellyfish system without necessary filtration or adequate flow. Not sure if you have a proper set up?  Email us and we'll figure it out together!  



Eon 10 gallon

• 12”L x 15”W x 20”H

• 10 gallons/ 32 liters

• Capacity: 20 small or 10 medium or 5 large

Eon 2ube

12.5"L x 15.5"W x 36"H

• 20 gallons/75 liters

•Capacity: 30 small or 18 medium or 9 large jellies.


How long will my jellyfish live?

This article refers to keeping jellies in small, home aquariums and does not necessary apply to commercial set ups.

Jellyfish in captivity, when maintained properly, will live about one year from start to finish. That is their normal life expectancy.  This being said, if you have a jelly that is 2” in diameter it is about 3 months old and you will have it to enjoy for about 9 more months.  If you have a jelly that is 3” in diameter, it is about 4 months old and you will have it to enjoy for about 8 months.  One year is one year-- from the time of strobilation (the time when the jelly is “born”) to the time that it grows old and dies.  So even though you received it in January, let’s say, it is already 3 or 4 months old and will only live for another 8 or 9 months until September or October---not until the following January. 

We always recommend initially purchasing and receiving jellies that are about the same diameter. We do not recommend purchasing jellies that are vastly different in size. And here is why…

When keeping a number of jellies in a closed system, the strongest jellies will emerge in the first two months and begin to get larger than the others.  This is “natural selection” and is normal.  You will see the larger ones grow and the weaker ones either stay the same size or get smaller.  It doesn’t mean you are doing anything wrong in keeping them, as it is a natural occurrence.  Therefore, purchasing jellies of different sizes does not allow for natural selection to take place. The larger animals you purchased will immediately out compete the smaller ones even though the smaller ones may be strong animals.

Do not overfeed in an attempt to get more food into the smaller ones.  Feeding them more may seem like a solution, but it is not.  Please read more about feeding and see some good examples of how much to feed on The strongest animals will win out over the weaker ones.  The only thing you will be doing is compromising your water quality and the overall health of your set up.  Let nature take its course and enjoy your jellies.  Even though the strongest ones get bigger, the smaller ones will be just fine and simply exist “as is” in your system and give your tank some size diversity over time.


How big will my jellyfish get?

This article refers to keeping jellies in small, home aquariums and does not necessary apply to commercial set ups.

In small home aquariums the jellies will grow according to superiority of the animal. Over time the strongest animals will emerge and out last the smaller ones and continue to grow. However, in small home aquariums up to 10 gallons, you are looking at 5” in diameter to be the maximum size. In larger habitats, of course, they have the room to grow bigger, as you might expect.


How long does it take to set up the Eon System?

It will take about 1/2 hour to set the tank up & add your pre-mixed and aerated saltwater. Then you will come back to and order your jellyfish (with your first order of jellies you will receive 3 free jellies and a month supply of food).  Your jellies will arrive the next day. You will acclimate and introduce them into your system that day. You will receive "seeded" biological material with your first order of jellies & you will add it into the filter box. It will help cycle the tank and establish your biological filters.  (Note: you will not do any water or filter changes in the first 4-6 weeks as your system starts to cycle and establishes itself.)

What does it mean to "cycle" my Eon System?

Excerpt taken from

The nitrification cycle is actually pretty simple. It can seem hard because of a couple terms that are not familiar in our everyday language. But basically this is a simple three-step process.

    Step One

The first thing that happens when you put fish in the tank is ammonia is produced. This is from the fish waste or excess foods that are decomposing.

    Step Two

As the amount of ammonia starts to increase, a bacteria forms called nitrosomonas. This bacteria begins to convert the ammonia into nitrite. As the ammonia is converted to nitrite, the amount of ammonia will begin to drop and now the nitrites will begin to rise. Soon your ammonia test will show no more ammonia in your tank. This usually happens within the first week and a half of a normal cycle. Nitrite is also very toxic to fish, though not as hazardous as ammonia.

    Step Three

As the nitrite levels increase, another bacteria forms, called nitrobacter. This second bacteria begins to convert the nitrite into nitrate. As it is converted to nitrate, the amount of nitrite will drop and the nitrates will begin to rise. Soon your nitrite test will show no more nitrite in your tank. This happens between three to six weeks in a normal cycle. Nitrate is harmless to fish but is one of the nutrients that plants and algae need and is the final product produced in the nitrification cycle. One of the reasons that water changes are recommended is to keep nitrates at lower levels.

 The time it takes to cycle an aquarium can be sped up by 'seeding' the aquarium with commercially prepared bacteria.  Then the entire cycle will only take between 1 - 2 weeks. This seed bacteria is available in either a freeze dried or liquid form. You can also add bacteria rich media from an established aquarium, like some of the gravel. The seeding should be done after ammonia is starting to form in the newly setup aquarium. You must wait until there is ammonia or the seeded bacteria will starve.

What is the typical upkeep for the Eon?

Once a week you will change 1 gallon of saltwater and the mechanical filter. You will also clean the all interior surfaces with a small acrylic cleaning magnet (Time: 30 minutes).  Every other week you will also exchange 1 of the three carbon filters (Time: an additional 5 minutes). Every three months you will clean out the spray bar holes and the drain screen, along with the pump and check valve (Time: an additional 15 minutes). The built in wet/dry filter will maintain your chemical & biological filtration and therefore, water quality and clarity on a daily basis.  Such a stable environment is exactly what the jellies need to thrive.
When do I place an order for jellies if I need them delivered on a specific day?

You can place your order at any time. Simply make a "Note to Seller" exactly when you want them delivered and we will schedule it. They will arrive via Next Day delivery. We ship Monday - Thursday orders that are placed before 12 noon PST.
One of my jellies is acting weird. What should I do?

Don't be too quick to react if one of your jellyfish is acting or belling differently.   Read "When your Jelly Takes a "Personal Day" blog post at for help understanding what might be going on. 

What is your Refund Policy?


Understandably, we are concerned about the welfare of our animals.  Many people do not understand that a specialized tank with proper filtration is necessary to responsibly keep jellyfish as pets. Therefore, to guard against misinformed purchases of live animals online, we reserve the right to cancel any live jellyfish order at our discretion.

All live animal sales are to be inspected immediately upon receipt.  If you feel you have received an animal that is not healthy, or is not alive, you must notify us within 12 hours from the time of delivery to be considered for a refund. Notification should be in writing via email including a picture of the animal in question & a description of the problem.  If you are purchasing live animals for another jellyfish aquarium not listed above, you are purchasing at your own risk and no refunds, reimbursements, exchanges or chargebacks will be honored unless previous authorization has been issued.  Unopened and unused dry goods can be returned within 30 days of receipt.  Shipping costs are non-refundable.  If you do not understand our refund policy, it is your responsibility to correspond with us prior to placing an order for full clarification.


What is the Fish-less Cycling Program and how can I sign up?

A Fish-less cycle is the fastest and safest way to cycle your aquarium without harming any jellyfish or fish. It involves placing a “pea” size (⅛” or 6mm) piece of raw shrimp into your filter box under the drip tray. If your aquarium does not have a filter box or drip tray, then you can place the piece of raw shrimp directly into your tank to decompose.

The decomposing raw shrimp will begin to create ammonia and start the cycling process. As your system goes through the cycling process you will check in with us once a week with a picture of your API test readings and we will both record your findings.

After about 2 weeks we will see the ammonia level rise and then start to zero decrease. Then the nitrite level will begin to rise. Maintain the proper salinity in your aquarium by adding a bit of distilled or RO water each week. After another 2 weeks, the ammonia will return to zero and the nitrite won’t be far behind.

Once the ammonia and nitrite levels return to zero, your system is cycled! Your pH will be a bit low, so conduct a 10% water change the day before receiving your new jellyfish. You must strive to always have a 0ppm level of ammonia and nitrite in your aquarium. Don’t overfeed and don’t do more than a 30% water change at any time.

The process of cycling a new aquarium is often overlooked and can create problems right from the get-go. Jelly owners who do not allow their tank to completely cycle end up with unhealthy jellyfish and become confused about why their jellyfish are not well. Cycling is a crucial step in starting a saltwater aquarium of any kind and in the survival of any saltwater animal, not only jellyfish. However, since jellyfish are 96% water and rely heavily on water chemistry, they need a biologically stable environment to thrive in. There is flat out misinformation going around the internet about how long cycling takes. It takes no less than 4 weeks; it's just biology. Even with the use of bio-starters, you must still cycle the aquarium and will still take 4 weeks minimum.

This is where we come in. We will keep track of your weekly water quality readings with you! You will need to purchase an API Saltwater Test Kit with pH, ammonia, nitrite, and nitrate. If you choose to participate in this program, you are agreeing to submit weekly water quality readings.

This is open to all jellyfish aquarium owners, regardless of type/brand. If you choose to participate in our Fish-less Cycling Program and complete it, you will receive an additional 3 FREE moon jellyfish with your first order of jellyfish. If you are an EON owner, you will receive 6 FREE moon jellyfish with your first order of jellyfish.

Sign up now by emailing us at with the following: (1) name, (2) email, and (3) type and size of jellyfish aquarium. We will get back to you with more information.