FAQ - Moon Jellyfish

Q: What are jellyfish?

A: Jellyfish are the simplest moving animals on our planet. They are closely related to corals and anemones and appear in the fossil record at about 600 million years ago. Jellyfish do not have a brain, heart, nervous system, internal organs or anything else. Jellyfish have a few simple parts; tentacles for capturing food, a swimming/pulsing bell for movement, oral arms for capturing and concentrating food, sensor spots along the margin of the bell (these sense light and gravity) to aid movement, a gut for digestion and gonads for reproduction. Some jellyfish are a little more advanced than others and actually have eyes like box jellies. Some jellyfish are a lot simpler than others like the moon jellyfish! Jellyfish come in almost every shape and color imaginable, some are upside down and some even produce their own light!

Moon Jellyfish

Aurelia sp. 1 (Japanese moon jellyfish) as seen in a Long Beach harbor.

Q: How do you ship the jellies?

A: The jellies ship in standard perishable boxes and we only ship Monday through Thursday (Monday – Wednesday for international orders). It is best to place your order over the weekend or on Monday so your order can ship out first thing, depending on how many orders we have your order may not ship until the following day. If your order is larger, a Styrofoam or air bag lined box will be used. It is important that you are home to receive your jellies, be sure to not have your jellies left at the door sitting in the sun, the box will overheat.


Our $34 flat rate only covers FedEx Standard Overnight service up to 10 lbs. - if you are out of the service area for standard overnight we will contact you for an additional payment to ship via Priority Overnight.


Q: How do you acclimate the jellies?

A: Acclimation Instructions:

1. Float bag, or container in bag,  in tank for ~1o minutes to match bag temperature to the tank temperature (should be ~75 F).

2. Open the bag and remove approximately half of the water using a cup or other small container.Do not try to pour the water out, you will pour your jellies out!

3. Add tank water to the bag, equal to the amount you removed.

4. Wait 10 more minutes and then release the jelly into your tank. Overall you want at least 20 minutes of acclimation time for your new jellies.

Q: What temperature is best for my jellyfish?

A: You are going to want to keep your jellyfish at a nice mild temperature, 70-72F is a great temperature to start at. If you have plenty of live food available you can try higher temps 75 or above, but there is really no reason to grow them this high unless you want rapid growth.

Q: What about salinity?

A: The jellyfish that PB ‘n’ Jellies sells are warm water, tropical, moon jellies well adapted to these conditions which include higher salinities. Your salinity should not be lower than 34 ppt or 1.0257 specific gravity. The ideal salinity for introduction is 38 ppt or 1.029 specific gravity which will cause your jellies to be slightly buoyant, this helps them adapt to your tank. Introducing your jellies to a higher salinity and having them “floaty” is much better than introducing them to a lower salinity and having them sink to the bottom where they will struggle to stay off the bottom.

Q: How long can jellyfish live?

A: Most jellyfish are seasonal and live less than a year, some only live for 3 months, but some can overwinter and live multiple years. Moon jellyfish are known to live in captivity for several years. In a small home aquarium you could expect a moon jelly to live for about a year, depending on the setup and space of course.

Q: What kind of tank do you keep jellyfish in?

A: A very simple one! Check out my blog to see how you can build your very own jellyfish holding/grow tank. You can also purchase a desktop jellyfish tank now. There are several basic types of tanks that can house jellyfish: kreisels (or true kreisels), pseudo-kreisels, stretch kreisels, cylinders and modified boxes, bullnose or bow front tanks. The last category are by far the easiest to build yourself, you can take almost any standard aquarium and modify it to meet the needs of your jellies. If you already have a successful reef aquarium, it is quite easy to tie in a separate jelly tank to your sump.

Q: How or what do you feed jellyfish?

A: Jellyfish can be fed a variety of live, frozen and dry foods. I prefer live food and use live rotifers to feed the jellyfish. You can also use brine shrimp, however they are very large and create a lot of waste (ammonia) as they eat, get eaten and die. Brine shrimp also foul your tank faster than rotifers will. A fouled tank will have dirty water and this can stunt the growth of your jellyfish or cause deformities resulting in eventual death/decay (jellies dont’ really ‘die’, they just fall apart or rot until they can no longer move and are a blob sitting at the bottom of your tank) Another tip… overfeeding is probably the most common mistake in jellyfish husbandry of closed systems. Back to jellyfish food, there is a bonanza of frozen and dry filter feeder foods out there that are appropriate for jellyfish. One of my favorites is Otohime TDO Size A.

Q: What happens if my jellyfish begins to fold up, gets damaged, stops pulsing or begins to fall apart?

A: Unfortunately you cannot do anything for your jellyfish, it is going to continue to degrade and eventually disintegrate. Jellyfish do not typically ‘heal’ when they are injured, while some very robust species can take a beating, most cannot and will perish. When tissue is lost, its gone forever. If enough tissue is removed, the jelly is a goner. In very rare circumstances, if a pre-mature jelly that is still growing is injured, it can still continue to grow and be functional.

Q: What happens if my jellyfish gets too big for my tank?

A: DO NOT release it into the wild, ever. It is illegal to release any animal into the wild or a public waterway just about everywhere without a state issued permit to specifically do so. Instead, seek out a local public aquarium, if they have a jellyfish display or breeding program they will most likely be more than happy to take it off your hands and give it a good home. If you absolutely cannot find someone to take it off your hands, contact us and we will find a home for it.