Is it easy to keep jellyfish? What are the 5 points to pay attention to?

Featured image source:Photo AC

What kind of creature is a jellyfish?

Jellyfish are a member of the plankton family that live floating in the ocean. It's definitely not a fish. They have a jelly-like body that is made up of more than 90% water. All jellyfish are poisonous, and the sting of some types is extremely painful, so you should avoid encountering them when swimming in the sea. Jellyfish have become popular as pets in recent years, and have become a hot topic for their cute swimming appearance. This time, I will introduce how to raise such jellyfish.

Is it difficult to raise jellyfish? easy?

To put it simply, raising jellyfish is "quite difficult." When breeding jellyfish, the ``aquarium shape'', ``water flow'', and ``water quality'' are very important. It is a continuous process of trial and error until breeding becomes stable. Arranging the aquarium so that the jellyfish can continue swimming, changing the water frequently... There's a lot to do. It's a bit difficult, but it can be said to be a rewarding creature.

Types of jellyfish that are easy to keep

moon jellyfish

moon jellyfish


When you hear the word "jellyfish," the first thing that comes to mind is probably the moon jellyfish. This type lives all over Japan, and is the easiest type to raise. Breeding is also relatively easy.

octopus jellyfish

octopus jellyfish


This is a jellyfish that lives in warm regions such as southwestern Japan and Southeast Asia. It is said that they live symbiotically with zooxanthellae and receive energy from the zooxanthellae through photosynthesis. Requires a lot of light.

color jellyfish

It is a jellyfish that lives in Southeast Asia and is in the same family as the octopus jellyfish. There are color variations depending on the species, and there are various colors such as blue, white, and brown. The water flow is stronger than other species.

red jellyfish

red jellyfish


This is a highly poisonous jellyfish that appears in areas such as Tokyo Bay. Although they are very beautiful when they swim gracefully, they have some drawbacks, such as having to make the aquarium large because their tentacles are long, and preparing food because they feed on jellyfish.


Among jellyfish, the jellyfish is a unique type. They stick upside down in the aquarium and move their tentacles to feed. It is a species that can be kept relatively easily along with moon jellyfish.


Jellyfish breeding equipment

Can you really keep jellyfish? You can do it surprisingly.

fish tank

It is convenient to use an aquarium specifically designed for jellyfish. Many of them are small, but this is the quickest way to use them. In the case of jellyfish, you can also keep them in a small cube aquarium with an external filter attached. You can also raise jellyfish by pumping air into a goldfish bowl to create a water flow, but this is not recommended as they tend to weaken and it takes a lot of time to change the water.


When breeding jellyfish, it is best to have a cooler. The appropriate water temperature for most types of jellyfish is around 15 to 20 degrees Celsius. It is better to have one installed, as higher water temperatures can lead to deterioration of water quality. There is also a dedicated jellyfish tank that can be connected to a cooler, so it is convenient to use it together.


A filtration system is also important when breeding jellyfish. Use filter media that has bacteria attached to it in advance. If you have installed a filter tank, it is even better to use a small protein skimmer together.

A breeding set is recommended for beginners.

Recently, breeding sets that include everything necessary for breeding jellyfish are on sale. If you are a beginner, we recommend using this set.

jellyfish food

The diet of jellyfish varies depending on the type, and there are two main types: plankton diet and jellyfish diet. Most of the creatures that are easy to raise, such as moon jellyfish, feed on plankton, and we feed them freshly hatched plankton called Artemia. Artemia breeding kits are also available, so it would be a good idea to purchase those as well.

5 things to keep in mind when breeding jellyfish

Breeding jellyfish is difficult! The reason I said this is that there are many things you need to be careful about.

Also read:  Oiso sand is a standard substrate material that is inexpensive and easy to handle! What is the compatibility with filters and aquatic plants?

① The water must be flowing all the time.

Jellyfish are plankton floating in the ocean. In the aquarium, you must always create a flow of water. If the water current is too weak, you won't be able to swim. If the water current is too strong, it will be washed away and weakened. The water flow must be such that the jellyfish can fluffy swim inside the aquarium.

② If air gets in, it's definitely no good.

If air gets into the jellyfish's cap, it will melt and die. Do not introduce air into the aquarium through circulation. Whether it's feeding them or cleaning them, it's no good if they make jangling noises.

③ Food is neither too much nor too little

The amount of food is also important for jellyfish. If there is too little, there will not be enough food and the jellyfish will shrink quickly. On the other hand, if there is too much food, the water quality will deteriorate and the jellyfish will become weak. Feed as much as you can eat at least twice a day. If possible, it is ideal to feed your pet sparingly and frequently.

④ Clean the aquarium frequently

If you leave your aquarium unattended, moss will grow, but this moss is also a natural enemy of jellyfish. Jellyfish may become weakened due to poor water quality, or their bodies may rub against moss and dissolve. It requires frequent cleaning.

⑤ Change water more frequently

This is where you need to be most careful. Jellyfish are sensitive to poor water quality, so frequent water changes are necessary. If you have a small aquarium without a filter, do it at least once a week, no matter how many days you have. At this time, it is ideal to use seawater that is exactly the same as the breeding water. Please be especially careful when making artificial seawater.

Let's collect jellyfish!

You can buy jellyfish, but the quickest way is to collect them from the sea. Gently scoop up jellyfish floating on the surface of fishing ports with a long ladle. Place the jellyfish in a thick sample bag, remove the air, and tie it with a rubber band for transport. Some jellyfish come to you when you shine a light on the sea surface at night. It's a good idea to take a short walk and look for it.

For those who think that breeding is difficult

Breeding jellyfish is difficult and troublesome, but you want to be healed by jellyfish. Recently, artificial jellyfish are being sold. You can admire colorful jellyfish in the aquarium. Of course no maintenance is required. It is also possible to create a stylish jellyfish aquarium with a particular layout.

Try raising jellyfish, which is difficult but soothing!

This time we introduced the breeding of jellyfish. It's quite difficult, but once you get used to it, there's no problem. One option is to try using a kit that allows even beginners to easily raise them. If you're tired and want to feel soothed by watching jellyfish swim, why not take this opportunity to try it?

Jellyfish breeding is difficult