Moon Jellyfish care sheet and breeding guide

There are two types of jellyfish, one with many short and thin tentacles such as moon jellyfish (Aurelia aurtita) and blue blubbers (Catostylus mosaicus) which feed on small marine plankton, and another with long and strong tentacles such as sea nettles and lion’s mane jellyfish which feed on small shrimp, fish and other jellyfish. In captivity, jellyfish are fed by freshly hatched live Artemia nauplii (baby brine shrimp) for short tentacles ones, and chopped up moon jellyfish or frozen sea food for long tentacle jellyfish. Preparing these foods for the jellyfish is the most challenging part of keeping jellyfish for those who want to keep them at home.

I said it is contradicting because to have water flow inside the aquarium, you need a water inlet, which means there is water suction. You cannot use an air bubbler either as jellyfish do not like the air bubbles. For this reason, jellyfish aquarium needs to have a spray bar which sprays the water inside the aquarium to make the circular flow, and a suction area large enough to spread out the water suction to avoid jellyfish being sucked away. A good jellyfish aquarium has a spray bar positioned in front of the suction area, which blows jellyfish away from the suction which results in an even less chance of them getting sucked.

There are some jellyfish that require lights for photosynthesis such as the upside-down jellyfish (Cassiopeia sp.), Spotted lagoon jellyfish (Mastigias papua) and Australian spotted jellyfish (Phyllorhiza punktata). They have symbiotic algae (Zoothanthellae) inside their body, which produces and gives energy to their host like corals. For those jellyfish, you will need a full spectrum light which is strong enough to grow LPS coral (200-300PAR). Even they have symbiotic algae in their body, it is important to feed them daily with live baby Artemia for their healthy growth.

The tentacles retract when they touch anything such as a tank wall or other animals including the same kind. So if you keep them in small tank, or with too many of them together, they will not have the chance to extend their tentacles fully. It seems to limit their growth and affect their health, and also they often get tangled if too many are kept in the same aquarium. Ultimately one jellyfish per tank is the best way to show the true beauty of those long tentacle jellyfish

To summarise, let us get back to the first question. Is it easy to keep jellyfish? I would probably say it is not too easy. It is not because they are complicated to look after, but more because the environment for keeping jellyfish has not been fully established yet. For example, if you would like to set up a reef aquarium, it is complicated but you can find all you need from an aquarium shop including coral, liverocks, fish, foods, lights, chemicals, tank, all equipment and husbandry information. If you would like to set up a jellyfish aquarium, you can probably find where to buy jellyfish aquariums, but you will need to find where to buy jellyfish and jellyfish foods, and almost no one can tell you exactly how you can take care of them.

One day in the near future, we hope that you can find various jellyfish in aquarium shops where you can also choose different jellyfish aquariums, equipment, food and all supplemental chemicals. Exotic aquaculture will keep working on developing and sharing the equipment, food and husbandry methods to everyone to enjoy keeping this beautiful marine creature.

Written by: Toshihiro Yoshida, 16 Jun. 2020