In any new industry that
pushes the edge or its traditional limits there are always
limitations. Itís 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
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 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
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.