Tuesday, January 3, 2012

How To: Easy DIY Jellyfish Kreisel Tank

For the longest time I could not find clear easy to understand plans for building a jellyfish aquarium. I read through several forums and spend a long time staring at pictures of tanks and trying to figure out how someone could make their own. No one was very detailed in their descriptions. Even "How to Keep Jellyfish in Aquariums" lacked a good set of plans and instructions. So Im out to give you detailed instructions on how to craft your own pseudo-kreisel Aquarium!

First let me explain what a kreisel and pseudo kreisel aquariums are. A kreisel aquarium is a specially designed aquarium meant for jellyfish or other delicate zooplankton, larvae etc. The design involves a larger chamber where the jellyfish reside. This chamber is either round or oval-esque depending on your sizing needs. Water flows on the edge of the aquarium walls to produce a very unique flow in the aquarium. This flow will keep jellyfish up in the water and moving, but still slow enough to let them swim freely and remain unharmed. Water generally exits this chamber through a screen. various meshes can be used depending on the jellyfish size. Water will then flow into a sump of somesort. this may be behind the aquarium or in some other location. This is where water will be filtered and heated or chilled etc. Water can then be pumped back over to the main chamber. This is where the difference in tanks comes in. Regular kreisel aquariums involve water being pumped into a small box that will gently dispense water in an even laminar flow fashion. A pseudo-kreisel uses just a spray bar. Pseudo-kreisel tanks are cheaper and easier to make, which is why I have chosen to cover them.

True kreisel design. 

A Pseudo-kreisel design. 

Now, lets set up a parts list.


  • Drill with various bits. 
  • Sharp exacto knife for scoring plastic. 
  • Heat gun. 

Parts list~

  • Standard 10 gallon glass aquarium. (20x10x12)
  • Around 3 bottles of aquarium safe silicone.
  • Mini Fountain Pump, 2" x 2.2" from aquatic eco systems
  • Heater (If the room is lower than average room temperature.)
  • Nylon screen from aquatic ecosystems. (1000 microns works for almost all jellies but ephyra. use 500 micron for ephyra)

  • Acrylic/ Plastic sheeting from Lowes. 
    • (2)    OPTIX 10" x 8" Clear Acrylic Sheet
    • (1)  DURAPLEX 1'6" x 2' Clear Acrylic Sheet
  • CPVC Pipe and fittings. 
    • Silver-Line Plastics 1/2" x 5' Ultra Pure Hot/Cold CPVC Pipe
    • (2) End caps. 
    • (4) 90 degree elbow fittings 
    • (3) T fittings
    • (1) Valve 
  • 1" flexible tubing. (less than 6 inches needed)
Here is a basic design of the aquarium. 
Alright, now we move on to the building process. First your going to want to cut all the acrylic up and fit it. The sizes should be,

  • (2) 10"x8" (these are the two pieces you bought, already cut at this size)
  • (1) 10"x6"
  • (1) 10"x12"
  • (1) 9.5"x4" 
  • Save your scraps! Some will be used towards the end! 
These sizes are approximate, as no aquarium is the same. You may need to do a little bit of sanding ( I      
had to).  The 2 10x8s will be used as the two bent pieces in the main rotational chamber. The 10x6 will be used as a support for the screen and the rightmost bent piece. The 10x12 will act as a wall between the screen and the filter chamber. The 9.5"x4" will separate the pump chamber from the filter chamber. 

So after you cut out all you pieces, you should slide everything into place to see if it fits well. You may need to take the exacto knife off some of that black plastic on the aquarium to get the acrylic to fit. Make any sanding adjustments as you require them.

Once everything seems to fit well, take it all out. You will need to first drill four holes at the top right corner of the 10x12 piece of acrylic. This drains water into the filter chamber and sets the water level in 
the tank. I used a 1/2" drill bit. 

Next, you need to bend those (2) 10x8s. I simply put the acrylic sheet in a vice clamp and moved the heat gun along in an even fashion until it was the approximate angle I wanted. The angle of the acrylic really isn't that important you just need to make sure it will allow a circular flow in the aquarium and still fit in the tank. When I heated the acrylic it seemed to form a set angle on both pieces. This ended up being perfect for the tank. 

Time to glue! Start by gluing one of the bent sheets of acrylic into the left most end of the tank. 

As that is drying you may wish to take a dry erase marker and mark sections off on your aquarium. first split the aquarium up into fourths. The main chamber is going to take up around 3/4s give or take. The other 1/4 is for filtration and pumping.  

Next your going to want to glue in the 10x6 piece right at the line marked for 1/4. 

Once that has dried then you can glue in the second bent piece of acrylic. This piece will be glued in attached to the 10x6. There should be a thing, long gap running in between the two pieces of bent acrylic. This will be filled in with scrap acrylic later. (If you didn't understand what I meant, see the video. hopefully that will help). 

So the rotational chamber should be finished. We can now move on to the Filtration sections. 

To start off take the 10x12 piece with the holes drilled in it and glue it in parallel to the 10x6, but with a 1 inch gap between the two pieces. Let that dry.  

Now you can glue on the last piece, the 9.5x4. This will go perpendicular with the 10 by twelve. You will need to tape this piece in place before gluing it so it stays in place. this piece will separate the bio filtration from the pump. So there should be a gap between the bio filtration and the pump chamber. This allows water to trickle through your bio media and into the pump chamber. 

Screen time! Get the 1000 micron screen. This comes in a large roll, so there should be plenty for mistakes or for other jellyfish projects and many other applications. I just ball parked the amount of screen I would need to fit the gap. Remember the screen goes right above the 10x6 piece. My screen was wrinkly when I got it and it would stay straight so I just ran it under some hot tap water. That fixed the problem up. So to glue the screen in just tape the screen in place. The take your silicone and make a continuos line around the screen where it touches acrylic. Then dip a finger in some water and use that finger to flatten the silicone down on the screen, so that the silicone will seep through the screen and glue  it into place. Afterwards just add some extra silicone to any edges of the screen if they are pointy. 

If you haven't already, take some scrap acrylic and use it to fill the gap between the two pieces of bent acrylic. 

Alrighty, everything dry yet? Wait at least 24 hours (48 is really best) and then we can do a leak test before we move on. There is a specific way you should fill the tank so it does not collapse under misuse. You should slowly fill the pump chamber and have the pump send water into the circulation chamber. If you just pour tons of water into the circulation chamber then you could damage it from the sudden heavy weight and force of the water impact on the acrylic. I just Fill a gallon jug and pour it into the pump chamber, start the pump, and fill the jug back up again. (If you have enough flexible tubing then use that to send water from the pump to the circulation chamber. If you don't have enough flexible tubing then you can hold off the leak test until after the plumbing.) I slowly add more water until the jug is empty, fill it up and repeat until the tank is full. 

Now you are going to need to watch the tank for a while. Looks for large bubbles coming from under the bent pieces of acrylic. This generally means there is a leak. and the leak might not start until some air has bubbled out from under the bent acrylic. This is because the pressure needs to drop under that acrylic before water will seep in through the leak. So just watch the tank for about an hour or so. You can leave the tank and do other things just make sure you check on it every now and then. If there are leaks then fix them with some silicone. If your leak free then you can proceed to the plumbing. :)

This is just a tad complex. I don't really have measurements for anything and you may need to refer to my video for most of this. I basically cut CPVC pipe from the large 1/2"x5' as I needed it. First cut about 3 inches of flexible hosing. Then attach that to the pump. (Btw your pump should have the largest tube adapter on it) Cut enough CPVC pipe to connect the pipe to the tubing and still rest at around level with the top of the tank. Then add an elbow piece. Cut some more CPVC to fit and so on. Hopefully my video can give you the gist of what Im trying to get at here. Again, I would be happy to answer any questions on this build, even if they seem stupid or worthless,  

I will explain more on the spray bar though. The spray bar should have 10 holes drilled in it evenly across the tube. Make sure that all the holes are in a near perfect line. Otherwise the water will come shooting out in various directions, invalidating the whole purpose of the spray bar. The spray bar holes should also rest just under water. This way the spray bar wont create micro bubbles. These bubbles can kill jellyfish or cause the jellyfish to float constantly when the bubbles get trapped in its bell. 

Alright, so get your spray bar assembled the way you like it and then you can glue the CPVC pipes together. Just use some extra silicone to glue the pipes together. Well your tank should be finished. all the acrylic should be glued in. The screen should be well glued in. And the tank should be plumbed. If you have waited 48 hours for all the silicone to dry, and you have tested it then you can fill the tank with saltwater. Again pour water into the pump chamber and let the pump fill up the rest of the chambers. Mix your salt around and test the salinity. Jellyfish are used to various salinities between 1.024 and 1.028 however two points lower or higher is except-able. You just want to make sure the water stays generally consistent. Add a heater if the water is too cold. Warm water jellyfish prefer water in the range of room temperature to around 77 degrees fahrenheit. Temperatures ranging 85-ish and higher become lethal very fast. 

Your also going to want to add some filtration material to the biological filtration chamber. This is the chamber right next to the pump chamber. I used bio-balls which work great but I had them lying around and you may not. Chad Widmer who wrote "how to keep jellyfish in aquariums" suggested using plastic army men. Really any plastic material will work as long as it has a lot of surface area for bacteria to grow on. I even added some choppy pieces of screen in with the bio balls.      

So the tank is full and running. Wait a few days for the bacteria to build up in the tank. Don't add anything live from pet stores, you will end up with so many different things in the tank trying to attack your jellyfish. Such as, hydrozoans, algae etc. I did however, add a live Nasarious snail to my tank, which I caught from the warm Atlantic ocean. I kept it in another salt water tank just to make sure it didn't have any sorts of voodoo on it. Then I just tossed it in the filter/ pump chamber. It picks up dead brine shrimp and jellyfish waste.

After a few days you can add jellyfish. I prefer to use this tank to grow out juvenile jellyfish, however it will support a few larger jellies. You can buy your Jellyfish online (Im going to be selling them in a few weeks) or use the tank to raise some babies. Brand new jellies aren't  quite big enough for the tank, give them a week or two of living in a large dish and the should be good.    

I hope you enjoy the tank, and your jellyfish. Moon jellies and comb jellies should do excellent in this tank. If you want to keep Atlantic Sea Nettles or Lion's Mane jellies then I suggest scaling the project up with say maybe a 20, 30, 40, 50 or even 60 gallon tank.  


  1. travis , could i get in contact with you ? i have some questions regarding to aquarium design..

    Let me know please..

  2. @antiquel

    my adres is ulysses the3theye dot com

  3. @antiquel

    Hey, I would be happy to answer any questions you have about the design. Email me at travis.brandwood@gmail.com.

    1. What is the DURAPLEX 1'6" x 2' Clear Acrylic Sheet used for. If you could tell me asap, that would be great.

    2. Also could u tell me the exact pieces of acrylic sheeting of which u bought from lowes.

    3. The duraplex 1'6" x 2' acrylic is used to be cut into smaller pieces, such as the 10"x6"

      The parts list should give you the exact name of the sheets as found in lowes.

  4. @antiquel

    Hey, I would be happy to answer any questions you have about the design. Email me at travis.brandwood@gmail.com.

  5. This comment has been removed by the author.

  6. Is the pump you listed the right one? I bought one from aquatic ecosystems and the pump seems small and the head (even with the big attachment on it) does not fit with the tubing listed. Thanks

  7. I would like to purchase a moon jellyfish. I recently bought an aquarium specific from the us only to find I can't purchase the jellyfish.

  8. Where did you get the screen material? This is the final part to my tank and trying not to have the most expensive part be the screen haha