Now, before you get into anything that has to do with jellyfish, you must know their life cycle.
Jellies have a very complex life cycle that includes 7 different stages.
Medusa, the most commonly known form. This is the stage where they have a full bell with stingers and oral arms. The medusae reproduce asexually. The male releases spermatazoa into the water which is collected by the female. The eggs are fertilized inside her
When they are ready to hatch, she releases them as planula larvae. The planula larvae swim around until they find a spot to settle.
Then they form into a polyp. The polyps clone themselves by asexual reproduction or "budding". The polyp then develops into a strobila which is a stack of around 10-15 ephyra.
The ephyra grow and develop and soon detach and become free swimming. They grow and grow until they develop a bell and become a juvinile jelly. It grows bigger until it becomes full sized (up to 12") Then the life cycle repeats.
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| Jellyfish Life Cycle. |
Getting polyps to strobilate (or transform into a strobila) requires turning up the tempature. You may also want to raise the salinity slightly.
I haven't had the greatest success breeding moon jellies, but I will keep trying 'till I get better. The ephyra require little flow, just enough to keep them off the bottom.
Here is a description of the anatomy of a jellyfish.
Some kinds of jellyfish (for example, moon jellies, sea nettles, etc.) need laminar flow which is a circular flow in a round aquarium designed to sweep everything off the bottom and keep it suspended. This can be done with a kreisel aquarium or pseudokreisel. Pseudokreisels are generally easier to make. All you have to do is put rounded edges in a box aquarium, make an outflow screen going to a sump and a spray bar spraying water over the screen to keep jellies off of it. Kreisels are a little more complicated and I won't go into them here, but you are welcome to go research them.
In this video, you can see how the jellyfish is moving throughout the tank as the laminar flow keeps him suspended.
Other jellies do not require laminar flow. In fact laminar flow will be unhealthy for them. Spotted lagoon jellies, blue blubber jellies, and upside-down jellies are some of the more common jellyfish. They are able to stay suspended by themselves (except for upside-down jellies which shouldn't be suspended). They require a tank with low flow so they don't get sucked up or blown around the tank.
Here are some videos of nice tanks for jellies without laminar flow.
The first one has upside-down jellies on the bottom and spotted lagoon jellies suspended.
Notice how their movements are much faster than the moon jellies.
And here are some blue blubber jellies or catostylus mosaicus.
If you want to keep a jellyfish aquarium, make sure you know a lot about jellies first. Know what to feed them, how your specific jelly's tank needs to be designed. There are a whole lot of other things you need to make sure of before you purchase a jellyfish.
You can start out reading this book. It's by Chad Widmer, who was once the Senior Aquarist at Monterey Bay Aquarium.
