In any new industry that pushes the edge or its traditional limits there are always limitations. It’s these limitations that can become opportunities for entrepreneurs and enterprising hobbyists. For certainly there is a new market developing, and it needs livestock. 

The Moon jellyfish, Aurelia aurita species is the most documented, and are the easiest to raise, of the jellyfishes. They are commonly recognized as a pale white pulsing disk with the four leaf clover design within their round bell. The bell is edged with a fringe of fine tentacles, called fringe tentacles, that pass food items to the four trailing oral arms. In most species of jellyfish it is these oral arms that contain the stinging cells and its also these arms that pull the food items up into the mouths of the jellyfish.

A Moon jellyfish starts life as a tiny white anemone looking structure called a polyp. This polyp attaches itself to almost anything. As with most Cnidarians a jellyfish polyp is composed of a central column that has a foot for attachment and an oral disc for the intake of food and exit for waste products. The oral disc has a fringe of feeding tentacles surrounding it, which bring food items to its mouth located in the center. It is this oral disc that segments, divides and individually separates from the polyp in what is called asexual division, budding, or also referred to as strobilation.

As a result of strobilation the oral disc portion of the polyp that segments and detaches from the main body of the polyp and pulses away. This pulsing disc, which resembles a small snowflake, is now a free swimming baby jellyfish called an Ephyra. Ephyra begin their pulsing before they detach from the polyp. It is this pulsing that is the main method of separation from the polyp and is the means of locomotion in jellyfish species. The pulsing is not just a means of propulsion but is also how the jellyfish moves its food items around and into its mouth and helps move fluids through out its body.

So, how do you get polyps, and how do you get them to strobilate and produce Ephyra? If one were to place a handful of freshly collected wild Moon jellyfish into a tank together chances are quite good that they will spawn within the tank or that females may already have been fertilized and are ready to release the planula ( eggs ) that are attached along the edge of her trailing oral arms. Once released these planula will settle within the tank and within a few weeks will develop into a polyp.

Pacific coast Moon jellyfish live in 53 to 68 degree waters. By using a chiller unit you can maintain the colder temperature water and then by allowing the temperature to rise, sometimes just two degrees, will often encourage the polyps to begin to strobilate or bud off Ephyra.

Up to this point a simple tank or glass jar with a slow flow of water through it could hold your polyps, but from this point onwards these small jellies, Ephyra, are in need of a flow or current that keeps them constantly suspended. This can be accomplished through the use of some slight aeration or a tank designed specifically to rotate or kept in suspension its inhabitants. If allowed to settle Ephyra will quickly become deformed or perish as a result of starvation.

The key to a Ephyra tank, or a jellyfish tank design is to create a means where the water enters and exits the tank, as well as, suspends its inhabitants weightlessly within the center, all without being visually obvious and without damaging the soft gelatinous bodies of its jellyfish inhabitants. There are a few designs on the internet. I understand the one using a drum shaped fish bowl submersed within another tank is quite successful. These same style tanks are also used by seahorse breeders.

At first Ephyra resemble a small snowflake but within a few weeks they go through a slight metamophisis. First is the development of what appears to be a tail extending from the underside which will develop into the four trailing oral arms. These oral arms are what will pull the food up into the jellyfishes body cavity. Next the radial arms that have formed the branches of the snowflake now begin to fill in between those branches with a solid tissue and develop into the more commonly seen bell or disc shape.

If you want more information here are two very good sources; a scientific article called Collection and Culture Techniques for Gelatinous Zooplankton by Kevin Raskof, Freya Sommer, William Hamner and Katrina Cross, and How To Keep Jellyfish In Aquariums, by Chad Widmer. Both provide details of the processes, systems and the needs to maintain, manage and to produce jellyfish.