This section is dedicated to keeping Jellyfish in an aquarium. Dr. T is a specialist in marine plankton and he will be happy to help with any of your jellyfish questions.


Postby Scanloni » 15 Jul 2013, 17:24

So I've had my first 3 medium jellies in my tank for about 3 days. Everything looked great. I even commented to my wife this morning about how healthy they looked. Just now I went to siphon some uneaten food from the bottom and was shocked to see that the jellies looked dead and the water was incredibly cloudy.

I took the jellies out and put them into another bucket with about a gallon of purchased salt water I had left over. I just rinsed the filter sponges and put them back in, turned the filtration pump to max, and now I'm not sure what to do. I don't have any test kits right now. I assume I need to change out some water, but not sure how much. 5 gallons? 10 gallons? All of it?

Not sure if I'm overfeeding because I simply cannot find any specific instructions regarding how much/how often to feed. I'm using frozen brine shrimp and the jellies seem to love it, eating the majority of what I offer them.

Any help is greatly appreciated. Thanks.
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Postby Scanloni » 16 Jul 2013, 13:30


After removing the jellies, siphoning out the uneaten food, rinsing the sponges, and letting the pump run at max for a couple hours, the cloudy tank began to clear. I turned the pump back down to minimum, and put the jellies back in the tank. They looked pretty weak all night, barely pulsing, and weren't feeding well. This morning they looked a bit healthier, pulsing a bit more, though still not 100%. They fed better this morning, but it's hard to tell since I'm offering less food than I was before.

Everything I read about "bacterial booms" recommended that if I essentially do nothing and ride it out the water quality will correct itself. As of right now, it appears to be true but we'll see....
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Postby Cubic » 16 Jul 2013, 14:32

Hi Scanloni

A bacterial bloom is always a risk when you first set up your tank. We recommend leaving the tank to cycle for as long as possible before adding jellies to try and avoid it.

The bacteria its self shouldn't have any ill effects on your jellies. The knock on effect of a bacterial bloom can cause problems though. Firstly, the bacteria are using oxygen so they can drop the tanks oxygen level and crash the tanks pH. The other issue is that when all the bacteria die off they can cause an ammonia spike and later on nutrient spikes which can effect your jellies.

We recommend getting a small air pump and putting an air stone in the back section of the tank to keep the oxygen levels up and the pH stable. You can also do regular small water changes (about 10-20% total a day) to export the bacteria. Its important that any water you use for water changes has been mixed for at least 24 hours before you add it to the tank because jellies can have a bad reaction to new salt water and this is even more likely if they are sick to begin with.

The other thing you mentioned that you are doing already is reducing the feed. This will help a lot.

Please keep us updated, I will a close eye on this thread now in case you need any more help.
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