The idea of keeping jellyfish is not necessarily a new one. The specialized tanks, life support equipment and the main food sources have also been around since the 1960’s. So, why don’t we see them all over the place? Why is it there are only a handful of companies over the past 50 years that deal with jellyfish in some way?
The challenge through the years in bringing jellyfish to the ornamental fish marketplace has been threefold; a consistent supply of jellyfish, user friendly and functional plankton kreisels and life support systems that don’t make the hobbyist want to pull their hair out in frustration, and an easily obtained, administered and nutritional food source. Of course, there will always be those who wish to tinker with and modify their systems with the utmost of joy and glee on their faces as they do it! Those folks also enjoy growing and making their own food sources for their aquatic buddlies. However, when trying to bring any of the specialized animals like the scyphozoan jellyfish Aurelia aurtia, Aurelia labiata (the moon jellyfish species) and Chrysaora fuscescens (West Coast Sea Nettle) to the marketplace, things need to be more turn key and easily accessible for the market to establish itself positively and, in turn, grow.
Over the past 15 years or so, things have really picked up speed when it comes to jellyfish marketability. In the early 1990s, the Monterey Bay Aquarium dazzled the world by exhibiting the first public jellyfish displays in a darkened exhibit hall, then came Cabrillo Aquarium in San Pedro, and from there on down the road until today public aquariums are continuing to install and expand their exhibit halls to include jellyfish of one species or another. Jellyfish exhibits have proven to increase attendance, which increases awareness and education of these graceful animals. The public was, and is eating up the experience of gelatinous zooplankton. It was only a matter of time that folks started to wonder and ask themselves, “Why can’t I have one of these at home?”
Well, you can! And it is getting easier and easier to do so.
Understand that there are several species of jellyfish coming more and more available, each with their own requirements and needs. Please be sure to research the type of jellyfish you want to keep before trying to find their particular tank and life support—they can vary. Here we are focusing on the cold water schyphozoan jellies, Aurelia aurita, Aurelia labiata and Chrysaora fuscescens; however, these tips are useful for any type of jellyfish and jellyfish tank hunting you might be doing. They may sound simple~ but they are very important to keeping jellies happy and healthy and growing!
You want to make sure that you have three bases covered when choosing a jellyfish tank and deciding to keep them.
BASE ONE: Check to see that the tank has Good Flow
1. Almost all jellyfish tanks need a certain level of rotational movement inside them creating a false current that aids the jellyfish in swimming or belling. Good Flow means nice and even turning over of water inside the kreisel area (kreisel is a German word meaning “ to spin” and has been used since the 1960’s in reference to jellyfish tanks). Gentle turning--not blasting or forceful. Gentle, even or what is referred to as laminar flow, comes with a good tank design. You can identify good flow fairly easily. Watch the jellies as they approach the spray bar. The jellies should not be battered by the force of the water coming from the jets. Also, you should not see tiny bubbles shooting from the spray bar. Bubbles are NO GOOD for jellyfish! (SIDE NOTE: That means even tiny bubbles created in a protein skimmer. Best not to have a protein skimmer at all). The flow should be as low as possible inside the kreisel area, while still maintaining enough “current” to keep the jellies belling naturally. Look for an even motion of the water. We don’t want what looks like “socks in a dryer” effect. A hap-hazard tossing of jellyfish all around the inside of the tank. They should be sort of floating—tentacle extended and moving naturally. You should be able to easily adjust the flow rate in to the kreisel area. If the tank doesn’t have a flow valve for adjustments~ you might want to look elsewhere. You will always need to adjust the flow. Smaller jellies require less flow than larger ones and if the system doesn’t allow for adjustment in the most critical area—flow rate---then forget it!
2. Good Food means a neutrally buoyant, equal to or less than 500 micron size (0.5mm) , enriched protein source. Of course, the West Coast Sea Nettle (depending on its size) can eat food twice that size or bigger, but it should still be enriched and neutrally buoyant in a jellyfish tank. What does “neutrally buoyant in a jellyfish tank” mean? It means that the flow inside the kreisel area should be sufficient enough to keep the food afloat and in the water column where the jellies can encounter it and eat it. If you see that the food sinks to the bottom, while the jellies are comfortable in the flow pattern that is set, then the food is most likely too large for the jellies to eat. The jellies will never “go find” that food at the bottom and eat it. It will rot there until you siphon it out. When looking into food products for your jellies, make sure to ask what the size is and which enrichment was used in the processing. Don’t mistake “enriching” with “soaking”. Enrichment is something that is ingested as a vitamin and mineral supplement by the animal. Soaking takes place after the food animal (in this case a type of brine shrimp or mysid or rotifer) is dead and most likely frozen and then soaked in some sort of vitamin/mineral supplement and then packaged. Some enrichments added to commercial feeds work great for fish, but can burn tentacles off and cause holes in jellies due to the acidic nature of it. Generally, don’t go for anything that is “soupy” and “cloudy” and looks like it has been soaking in something. These sorts of feeds will have an acidic quality to them as the food animal never ingested and metabolized the supplement. They simply soaked in it. These foods should be rinsed with some water from your system prior to feeding it out, if you choose to use. If it is frozen, thaw it first and take a look at what it is you are putting your jellies in contact with. If you are hatching your own brine shrimp, great! Be sure to feed it to the jellies after rinsing it well with some system water. Especially, if you are enriching your nauplii with selco for 12-24 hours~~~RINSE! RINSE! RINSE! With tank water! Get that residual selco off the nauplii!
BASE THREE: Start With and Maintain Good Water Quality
3. Good Water. Good heavens~ that is a vague and open-ended request! What on earth does that mean? For jellies it means RO/DI water. Never tap water, I don’t care what conditioners you add to it - never tap water and never bottled water. Bottled water is not regulated by the FDA in any way and can be simple tap water in a pretty and expensive bottle. Invest in a RO/DI unit and a high end salt mix without phosphates or nitrates. Always pre-mix your water and aerate for 24 hours prior to use. Don’t forget that!!!! Write it down. Water changes should be made weekly, 5% is sufficient as long as you are changing filters every week and rotating out carbon bags every month. Never make the changes directly into the kreisel area, but at the farthest point like into the drain area. This allows the top off water to mix a bit before entering the kreisel area. Maintain a pH of 8.0-8.4, Salinity at 63°F should be 33-35 ppt. (That's salinity and not specific gravity!).
The main thing to consider when thinking about owning a jellyfish and purchasing a jellyfish tank is to take it slow. Start small and grow into it. Make sure you understand what it is going to take to keep them happy and thriving. Know your suppliers and know where your animals are coming from and what their water quality parameters are prior to shipping to you. Ask for acclimation procedures from the shipper and always ask questions if you don’t understand.