Thursday, August 28, 2014

Water Quality in Jellyfish Tanks

What kind of tests should you be doing on your jellyfish tank and what levels are safe?

Jellyfish are interesting creatures in that they often appear okay with less than perfect water quality. They don't show many obvious signs and the jellies aren't talking. So what should you be testing for?

A good, basic and inexpensive test kit. 

Here is a list of the most important (In my opinion) factors to monitor in your jellyfish tank,

Ammonia- Ammonia is toxic to most invertebrates at low levels. Jellyfish have a knack for surviving in fairly high levels of ammonia that would easily kill other aquarium life. That being said, they might be surviving but certainly aren't thriving. Ammonia can burn at their tentacles and cause them to stop eating. High levels of ammonia also seem to be a factor in how long jellyfish live. It's best to keep ammonia as low as possible, as it affects their health in the long run.

Causes: Over feeding is the biggest cause. Dry or preserved foods are big ammonia creators. Having a good cycled aquarium with plenty of helpful bacteria will reduce ammonia build up.


  • Complete more frequent water changes and ensure that your tank has enough bacteria in it. This can be accomplished by seeding your tank with water from an established system or by adding any of the readily available "bacteria in a bottle" cycling products.

Nitrates- Nitrates are far less toxic than ammonia, but they accumulate over time. They are a product of ammonia being broke down. Nitrates tend to harm jellyfish in similar ways that ammonia does. High levels can slowly harm the jellyfish and cause an overall shorter life. Another side effect of high nitrates are increased bacterial and algal growth. Bacteria can feed on nitrates. Having a tank with really high nitrates can cause increased bacterial infections in jellyfish.

Causes: Nitrates tend to build up in aquariums over time. They accumulate due to a lack of frequent water changes or not enough to meet your systems production of them.


  • Water changes are the quickest way to lower nitrates. It's far better to stay on top of your water changes to begin with rather than doing massive water changes later. Jellyfish become used to high levels of nitrates and the sudden and rapid change can actually harm them more. 
  • There are a number of chemical filtration medias available to remove nitrates. Some work and others are just hype. They may be worth a try to lower your maintenance. Bio reactors are also a new form of nitrate removal. The employ the concept of growing bacteria on bio-plastics so they will remove the nitrates for you. 

pH- pH is another sneaky problem in jellyfish tanks. It slowly changes over time and suddenly your pH is way off. pH tends to be an issue when it becomes too low. This becomes an issue as the water leans towards acidic. The jellies can be burned and tend to have trouble consuming food.

Causes: Rotting food or dry and preserved foods tend to lower the pH. A lack of water changes will also result in lowered pH as various elements in the water are depleted.


  • Rapid changes in pH can be very dangerous to jellyfish. Use a buffer or basic (high pH) chemical to slowly bring up the pH over several days. Such chemicals include baking soda and sodium hydroxide. Note that sodium hydroxide will bring the pH up substantially as it is a very strong base.  A number of saltwater buffers are available at pet and fish stores, already mixed and ready to add. 

It is also a good idea to test for phosphates, nitrites and your alkalinity. These tests are important as well, but seem to have less of an effect on jellyfish. Phosphates can induce algal and bacteria growth as well.They are an issue with dry or preserved foods. Water changes will remedy them.

Remember: Nothing is better for your jellyfish than frequent and routine water changes!

Picture credits

Monday, August 18, 2014

Breeding Atlantic Sea Nettles Part II

Success! I have successfully bred my first Atlantic Sea Nettle! I'm extremely excited about the little guy. Its maybe 3/4" in diameter right now. Believe it or not, the jellies' tentacles already stretch 8"!

I had a large batch of Sea Nettle ephyra born early last month. There were probably 80 total. Everything was going well and they were all slowly growing. Then I had a large die off,  leaving me with 3-4. Well in the end, two of them pushed through. I needed to move them from their mini grow out tank to something larger. In the process of experimenting, I killed one more. So I was left with one Sea Nettle. I babied this thing like it was my own child. And it's grown to a stable size now. I will give a little bit of info on how I did it.

So I raise the brand new ephyra in a jar/beaker or round tank that uses air to circulate the water. The ephyra are pretty small so they need a small tank to ensure they feed well. The smaller the tank, the more likely they are to bump into their food. So this meant an empty yogurt tub for me! It worked pretty good. I conducted water changes every few days and fed them daily. When they got larger, but were still ephyra, I moved them to a round beta tank and used a bubbler. I liked this design a little more. This is where the ephyra really grew out. It almost seemed like more frequent water changes bothered them. That has no real scientific evidence to back it up though.

Once the juveniles grew out some of their fine tentacles, I moved them to psuedokreisel tanks to grow out. My one last Sea Nettle is still growing out right now. Ive caught many wild Atlantic Sea Nettles from North Carolina to Florida. They are always beat up with really short tentacles. The Sea Nettle Im growing right now is absolutely pristine. It's amazing how much of a difference captive raising can be!

I'm giving my polyps time to rest, but I would like to get another batch of ephyra going, and give this a third shot!

Tuesday, August 5, 2014

Mangrove Box Jellyfish

Hello, I do apologize for the gap in my blog posts. I've recently moved to Boca Raton Florida. I've been up and down the beaches looking for jellyfish all over. I've found a few. There are mostly Comb Jellies and Upside Down jellyfish here. I did find one other species, the Mangrove Box jellyfish (Tripedalia cystophora).

These are some seriously cool jellyfish. They are small box jellies that have bell lengths of about 1 inch maximum. Their tentacles may stretch and additional 1-1.5 inches. Their sting is not very powerful. Some people describe a definite burning or itching and others feel nothing at all. I've personally not felt much, but I credit this to my common handling of jellyfish. Tripedalia have four eyes at the bottom of their bells. They can use these eyes to sense solid objects in from of them. I tested this by placing a hand in front of one. It was heading straight towards my hand and turned away, dodging it. Impressed, I tried it over and over. The same reaction occurred. We are dealing with some "smart" jellyfish here.
Tripedalia cystophora with full extended tentacles. 

 I've caught quite a few and had the chance to study them a little. The adults are obvious as they are colored orange. The orange color comes from the planula or reproductive material they hold. Females hold planula until they are mature. This means you can find a single mature female and start a polyp culture. I started my own culture of polyps. These jellies are invasive and breed very easy. They planula settle anywhere and very quickly (1-2 days). Unfortunately the polyps are very tiny. A stereo microscope helps a lot. I'm still currently working with the polyps.
Microscope image of the polyps. At most, I've seen the polyps grow 4 tentacles. 

These jellies are picky eaters. The wild caught specimens don't react much to common jellyfish foods. I tried baby brine shrimp, adult brine shrimp and multiple dry fish larva foods. None of them really worked. I noticed a few jellies ate very fresh baby brine shrimp. After a few discussions with other aquarists, I found a little more on their diet. The wild jellyfish are used to eating wild Copepods. They hunt these pods down actively. Wild caught specimens will likely need Copepods. Captive bred specimens can be fed brine shrimp and are raised a lot easier. So the best thing to do is grab some jellies and use them to start a polyp culture.

The white pouches running up the bell contain reproductive tissues.