Jellyfish

It is possible to keep Jellyfish in aquariums, but it is important that you understand how their requirements differ from those of aquarium fish. If you keep your jellyfish in a standard rectangular aquarium, the jellyfish can become trapped in one of the corners and unable to free itself. A circular aquarium without any corners is therefore a much better home for your jellyfish. You must also create currents in the jellyfish aquarium, since jellyfish depend on currents in the wild. The currents has to flow in a special way in the enclose aquarium space to avoid the jellyfish from being sucked in and injured.

Since jellyfish is a difficult species to keep it is advisable that you have plenty of previous aquarium knowledge before your embark on such a project. The two most commonly kept jellyfish species are both marine jellyfish, and prior experience with saltwater aquariums is therefore recommended. It can be difficult to find the necessary equipment for a jellyfish aquarium in your local fish store, but do not let this discourage you. Several larger and/or more specialised aquatic shops are to be found on the Internet and you can have your equipment mailed to you.

One of the most commonly kept Jellyfish species is the Upside Down Jelly fish (Cassiopea andromeda). This jellyfish species originated from Philippine water, but can today also be found around Hawaii. It is believed to have been involuntary introduced to the Hawaiian fauna by ships around World War II. If you want to keep an Upside Down Jelly fish you must create an aquarium with an upwards water flow than can lift the jellyfish from the bottom. When you choose aquarium you should bare in mind that a fully grown Upside Down Jelly fish can reach a size of up to 20 centimetres / 8 inches in diameter. Upside Down Jelly fish eats micro plankton. The Upside Down Jelly swims upside down since this jellyfish depend on specific algae that it forms a symbiotic relationship with. By swimming with the algae on top, the jellyfish makes it possible for the algae to absorb sunlight and carry out photosynthesis.

Another jellyfish species that is sometimes kept in marine aquariums is the Moon Jellyfish (Aurelia aurita). It can reach a maximal size of 30 centimetres / 12 inches, and a large aquarium is therefore necessary. If you touch your Moon Jellyfish it can sting you, but the sting is not dangerous as long as you are not allergic or extra sensitive. Just like the Upside Down Jellyfish, Moon Jellyfish feed on micro plankton, but the Moon Jellyfish will also eat larvae in the wild and aquarists that keep Moon Jellyfish will therefore usually feed their pet large amounts of live brine shrimp. Moon Jellyfish is commonly found in temperate waters and you should keep the water temperature between 12 and 18 degrees Celsius / 55 to 65 degrees Fahrenheit in your aquarium. In many cases this means that you will be required to install a refrigeration unit. If you have a cool room, such as a basement, it can however be possible to successfully house Moon Jellyfish without any refrigeration unit