For a long time, aquarists have wanted to keep jellyfish. In the past, it seemed like an impossible feat. Not because jellyfish are particularly sensitive to aquarium life, but because their jelly like (boneless) bodies have the terrible habit of getting stuck in circulation pumps, filter intakes, or overflow drains. A traditional reef aquarium is certainly no place for a jellyfish, and it’s only a matter of time until they are sucked up by filtration, or shredded to bits by a propeller pump. When I first stumbled upon Jellyfish Art, I sort of chuckled to myself, thinking that it was impossible jellyfish keeping would become popular, or even easy. I had watched several of my aquarium pals invest some serious dough in a “jellyfish aquarium” with no luck whatsoever, just a lot of wasted dollars and a few dead jellyfish.

Suddenly though, a few aquarists I know were giving Jellyfish Art’s all-in-one jellyfish systems a shot, and they were reporting great results. Had this small crowd-funded start-up discovered the “art” of jellyfish keeping? What had changed, making something seemingly impossible to keep, suddenly possible in a small pico-environment? To find out for myself, I decided to give a Jellyfish Art system a try. Needless to say, I am pleasantly surprised, even thoroughly impressed with the results. 

Kreisel tanks:

Successful jellyfish keeping owes everything to the advent of kreisel tanks. Kreisel is a German word meaning “spinning” or “gyro-scope.” A kreisel tank is entirely round, and the filter overflow is a screen without any large openings. It only allows water and very small particles through, preventing jellyfish from making their way into a filtration chamber. In a kreisel tank, all filtration is separate from the main aquarium, and circulation is accomplished by a specialized piping return, which both creates a gentle gyre through the round tank and prevents jellyfish from getting entangled. Kreisel tanks create a non-stop circular gyre, which jellyfish can drift through much like they would in an oceanic current. They sort of work for jellyfish, like endless pools work for swimmers. These tanks were designed to raise jellyfish, or larval stage fish and seahorses.

The Jellyflap Aquarium:

Jellyfish Art owes a lot to the kreisel design, and their $ 399 Jellyflap Aquarium is essentially a stylish kreisel tank. The tank is entirely round, with the back sticking out like half of a large basketball where filtration is located. The display area is separated from the filtration chamber by a black plastic divider, much like is seen on various nano-cubes. The front viewing panel is lined in black, with a dark black background, creating a similar experience to the jellyfish portholes often seen in public aquariums. Considering the Jellyflap is only 1.8 gallons, it works well as a desktop aquarium.

Everything is well designed, with a keen eye to simplicity and function. The filtration chamber has a clearly identified MAX and MIN water level, and a top hatch opens revealing a small return hose and three bright, color-changing LED lights. It’s a sharp little tank and is built with the same quality seen in any nano-reef aquarium. The tank’s lighting comes with a remote, allowing the aquarist to select any color of the rainbow to highlight their jellyfish with. Also, the brightness of the overhead light can be adjusted.

Setting it up:

You can tell that Jellyfish Art is marketing their tanks to folks who have little, if any aquatic experience. This is something they hope people can use to decorate their homes, or create an exciting conversation piece with. The Jellyflap kit comes with everything a new aquarium keeper would need, right down to a siphon house and water change bottle. Salt is included, as well as live rock rubble for filtration and a small packet of Chemi-Clear Blue. Jellyfish Art recommends setting the tank up per their instructions, and waiting at least 24 hours before turning in your voucher for jellyfish, and having your animals shipped.

For those of us with reef aquariums, this process can be greatly accelerated. I simply filled my Jellyflap with some water from my reef, and stocked the filtration chamber with live rock rubble from my refugium and the included Chemi-Clear Blue. Essentially, it’s an instant aquarium and it would be possible for reef keepers to have their Jellyflap arrive with jellyfish, as it took less than 15 minutes to have the tank up and running. If you don’t have a reef tank, then I would recommend following Jellyfish Art’s instructions, and perhaps waiting several days before having your animals shipped.

Moon jellyfish:

The jellyfish sold and promoted by Jellyfish Art are moon jellies, Aurelia aurita. They are actually one of the most studied jellyfish species, and easily distinguished by their four horse-shoe shaped gonads, yes gonads. Moon jellies are entirely translucent, and under the right color of lighting are quite beautiful. They have paper thin tentacles and swim with a simple pulsating motion, drifting softly in the tank’s gentle current.

Considering that moon jellies are found throughout the ocean, from the tropics on up to the cold northern Atlantic, they can tolerate a wide range of temperatures. As long as the tank is staying between 49 degrees F to 70 degrees F, you shouldn’t need to worry about a heater or chiller for your jellyfish. Moon jellies also tolerate low oxygen environments quite well, meaning that they don’t require any additional circulation or aeration, other than what is provided with the tank.

In the wild moon jellies feed on plankton, grabbing their prey with nematocyst laden tentacles, tying it with mucus and pulling it up to their gastrovascular cavity. Once in their cavity, digestive enzymes break down the food. Jellyfish Art provides a jellyfish food (which requires refrigeration). They claim it’s a nutritious planktonic blend, although it looks a lot like brine shrimp eggs to me. Watching the jellies eat is fascinating, as you can see the prey moving into the gastrovascular cavity and breaking down slowly as the jellyfish digest. I would imagine moon jellies could consume a lot of the planktonic food used for corals and other invertebrates, however Jellyfish Art recommends only feeding their food, largely since uneaten pieces are easily siphoned out. I personally haven’t fed anything other than the supplied jellyfish food, and have found it easy to feed and the jellies seem to snatch it right up.

I will note that moon jellies are susceptible to metazoan parasites, so that is something to be aware of if using rock and water from an established reef tank. Also, adult (medusae) moon jellyfish only live for about a year, under the best conditions. If you’re especially lucky, you might get a full 18 months out of them, but moon jellies are not long lived creatures, so plan on replacing your jellyfish collection over time.

Final thoughts:

I am thoroughly impressed with Jellyfish Art’s Jellyflap tank, and the quality of their jellyfish livestock. I assumed when redeeming my voucher (which is included with a tank kit) that I would get a few dime sized jellyfish that you could barely see. Instead I got healthy, beautiful and appropriately sized moon jellyfish that have impressed everyone I’ve shown them too. If you’re looking to add some diversity to your fish room, a Jellyflap aquarium is the perfect way to do so. They would also be a perfect addition to a classroom, as the tank is small and doesn’t require any previous aquarium knowledge to set-up. Moon jellies as a species offer a bit of room for error and learning, making them a good choice for home aquariums.