Wednesday, April 18, 2012

Jellyfish Tank Crash and Mysterious Polyp

So the 20 gallon jellyfish grow out tank nearly crashed this week. I saved the one remaining jelly from inside before the tank went all the way down. The problem was the filtration. I tried anaerobic (bacteria that don't need oxygen) filtration this time to see how it would work. The anaerobic bacteria weren't very effective in this system. The tank got really dirty and grimy fast. Due to the inadequate filter system I had to set an internal box-style filter in. This subsequently boosted the suction on the screen. I overlooked that factor and about 6 new ephyra disappeared overnight. The surviving jellyfish will be cared for in a beaker with an air hose to keep it moving. Right now I'm in the process of upgrading the filter system. I cut the drain holes on the tank into slots to allow better flow. Im also going to silicone a trickle plate in place. A trickle plate is simple a sheet of plastic with holes drilled in it. Water drains onto the plate and drips over the bio media.

My Fantastic work at melting the drain holes into a grate style drain. 

The mysterious polyp finally strobilated. It released 3 baby ephyra. It looks as if a few more could have been born but they were very damaged. I saw one ephyra that was born with 1/8 of its normal body tissue. it was quite strange, and mildly sad. The new three ephyra seem to be very healthy. I've moved them into my 8 inch culture dish on top of the magnetic stirrer. From here I am going to raise them and see what I get. Im hoping for cannonball jellyfish, but there is still the chance of them being moon jellyfish.

Now, the mysterious ephyra are occupying my only 8 inch dish. I've decided Im going to be setting up a new system for moon jellies. I want to eliminate the need to raise the brand new ephyra in a dish. This takes lots of time and I can only raise around 7 ephyra at a time. As I learn more about raising moon jellies I  make plenty of mistakes. I cant afford to only raise 7 at a time. So I'm going to use a tank design from the blog Jellyfish Aquarist ( The tank is simple and cheap. I save the major details for another post, but I will post a "teaser" image.

Tuesday, April 10, 2012

Swimming with Jellyfish

My cannonball jellyfish still appear to be doing very well. I was curious how their tank was doing, and I wanted to take a look. So I threw my swim suit on, grabbed a snorkel mask, and dove in. It was quite interesting swimming in the tank with my jellies. I had to very careful not to kick any jellies or stir them around too much. Overall they appeared to be fairly content with my presence. I couldn't stay long. After about two minutes the jellies begin to secrete a stinging mucus. Obviously stinging mucus is no fun to swim in. So the second time I dove in, I recorded my experience. Reminds me a tad of Jellyfish Lake in New Zealand. I will have to visit that place someday. :)

I will also take this time to update more on the cannonball jellyfish~

So as of right now, the Cannonball jellyfish in my 200 gallon aquarium are doing fine. The bigger one, which was previously fairly inactive, has begun to pulse around here and there. He is still healing up the scratches in his bell, but the process is going by fairly quickly. The smaller one is doing quite well, as usual. Last week it got stuck next to a heater and burned a curve shape into its bell. I removed the heater and set it in the center. The curve has already completely healed up.

Feeding - I've noticed that these jellies eat a ton of food. They are literally eating 4 times as much food as the moon jellies would. Needless to say, I cant keep feeding them the expensive decapsulated brine shrimp.  I've noticed the jellies will also eat the eggs whole, unlike the moon jellies. Im thinking I may try decapsulating brine shrimp eggs myself. Ive also done some research on their natural feeding habits. Cannonball jellies tend to eat lots of oyster eggs. I may also look into buying some oyster eggs off the internet. They seem to be expensive, but I don't plan to use the oyster eggs as a staple for the jellyfish. 

Tank upgrade- The tank cant run forever without a filtration system. So as filtration I will be taking a second tank (exact copy of the first) and use that as a pseudo-sump. The tank will be full of some sort of bio media, sand, plants etc. The second tank, being 200 gallons as well, will double the volume of the system to 400 gallons.

Im hoping the sump will help filter the aquarium, remove nitrates, and provide a source of food. Adding copepods, amphipods and other tiny crustaceans will allow the jellyfish to be surrounded by plankton in at least some quantities.

Thursday, April 5, 2012

Mysterious Polyp Appears!

A few weeks ago I was examining my 20 gallon moon jellyfish grow out tank. I noticed a lone polyp living on a piece of sea weed in the tank. Naturally, I extracted it from the tank and put it in a dish. At first I assumed it was a moon jellyfish polyp that had some how made its way into the tank. This was very possible, polyp tissue is sometimes left over from ephyra and may develop into a polyp. But I later realized the polyp was growing on some seaweed that was in a bucket with 4 cannonball jellyfish when I was at the beach. This left a great chance of it being a cannonball jellyfish polyp now. This got me excited and so I put it, still attached to a chunk of seaweed, in its own petri dish.

Average Moon jellyfish polyps.
I examined the polyp further, to find any differences between it and the moon jellyfish polyps I have. I noticed the mouth structure of the mystery polyp was more elongated and almost tube like. Moon jellyfish polyps never seem to have this mouth structure, but rather a flat hole as a mouth. The mystery polyp also seemed to be shaped very slightly different, and was slightly larger than the average moon polyp.
The mysterious polyp, before being removed from the tank. 

That being said, by all means the polyp could still be a moon jellyfish polyp. studying such tiny organisms is hard and many changes can easily occur between two induviduals. This makes it hard to judge the species. So in order to truly find out the species i will need to wait for the polyp to strobilate. If I have to I can grow out a mystery ephyra and see what it produces. But I found an interesting observation on polyps by a scientific article. In a study done on cannonball jellyfish, the polyps were found to produce only 1-3 ephyra per strobilation, often two. The article also explains that they had trouble raising the polyps as their water quality declined fast. My water quality is very consistent, as I buy stabilized ocean water for my polyps and ephyra. That could lead to more ephyra.

So the polyp has begun to strobilate. Almost perfectly the mystery polyp and a moon polyp are strobilating at similar times. The moon polyp is about a day ahead. I've noticed the mystery polyp is a little slower, but that could be due to several variables. The mystery polyp also started with 2 cleaves and has grown to 4-5 (a cleave is referring to the cleavage in a polyp where it begins to form disks and each disk is a jellyfish).

The next few days may be critical in deciding if it is a cannonball jellyfish polyp or just another one of my moon jellyfish polyps. If I cant tell from the strobilation the ephyra should begin to look very different from a moon ephyra within a few days. Moon jellyfish and cannonball jellyfish are vastly different. I find it strange how they look so similar at these stages.