Egg Tumblers are designed to simulate the conditions inside a mouth brooding fish’s mouth. Mouth brooders will incubate their young by “tumbling” the eggs, although at first glimpse it may appear as though they are chewing gum! This motion ensure that enough oxygen and fresh water circulates around the eggs.
There are many DIY Egg tumblers floating around the internet. Some of the ideas in my design are not original, so many thanks to those who have been kind enough to offer their designs to hobbyists.
Some earlier attempts at making my own tumbler failed miserably and I lost a few dozen viable eggs due to it’s poor design. I then considered purchasing an egg tumbler from the local fish store. The price was around $40. Ouch! It seemed as though there was nothing to them, even the raw materials wouldn’t cost a fraction of what the store was charging. So it was back to the drawing board!
After some deep though and a lot of researching I decided on the materials i would use to construct my own.
1. Air pump
I wanted an air driven design as I had many old air pumps kicking around the fish room. Some other designs that I’ve seen use the diverted flow from a powerhead to tumble the eggs. In my opinion a powerhead is too big a hammer for this job, and a waste of electricity that is already at a premium.
2. Fluorescent light tube covers
These are a clear plastic tubes with caps on each end. The tubes are used in areas where there is high humidity to protect and prolong bulb life. The tube covers can be found at most hardware stores with a lighting section. Compared to acrylic tubing the price was very reasonable. The Tubes may not be as strong as acrylic but you can make 4 tumblers from a single 48″ tube cover. They can also be cut with a sturdy pair of scissors so you don’t require any specialized tools.
3 . PVC joints
One 90 degree 2″ elbow
Two 2″ couplings
I used the white 2 inch PVC because it slid quite snugly into the fluorescent tube covers. I would make sure to test fit these while at the hardware store.
4. Small piece of plastic window screen
I chose the plastic or polyester variety because i figured it would be less toxic and not as sharp as the metal variety. I experimented with a few different sizes of fish net netting but found it too flimsy and fragile to be used in this project.
5. Length of airline tubing
The airline tubing needs to be long enough to reach from your tumbler to the air pump.
6. Suction cups
Suction cups, or old suction cup carriage to hold the tumbler in place against the tank glass. If you don’t have one of these and have found another method to float the tumbler in your tank, please let know what you used!
- Start by cutting two lengths of plastic tube. One at roughly 3 1/2 inches for the egg chamber, and the other around 6 inches. You can experiment with different sizes if you like but I found these dimensions make the best of the smaller air pumps that I have, and with the total height being around 12-14 inches, the finished tumbler can still fit in my smallest fry tank
- Cut out two 3 inch square pieces of nylon window screen. They don’t have to be perfect because you will trim them to fit after assembly.
- Sandwich one piece of window screen between the smaller plastic tube and one of your PVC couplings. This creates the bottom of the tumbler.
- Sandwich the other piece of window screen on the other end of the smaller plastic tube along with the second PVC coupling.
- Slide the longer piece of plastic tubing over either end of your egg chamber.
- Slide the 90 degree PVC elbow on the top of your longer plastic tube. IMPORTANT : You need this 90 degree bend to allow the water to be displaced in your tumbler. With a straight vertical riser, the bubbles will simply surface and push the water to the sides of your tumbler but not draw water from the underside, which gives lift to the eggs. When you put the tumbler in your tank make sure that the elbow is directed away from the glass for best results.
- Attached a suction cup carriage to your tumbler. I used a broken one from and old power head with a couple of elastic bands. I’m sure there is a better way, Zip ties?
- Slide the airline tubing in through the 90 elbow opening right down to the top window screen. You can adjust the flow by raising or lowering the air tube, alternatively you could attach a gang line valve or air flow regulator if you like.
- Your done! All that remains to do is to place your fertilized eggs in the egg chamber and suction it to the side of your Aquarium. I find it’s best to use a turkey baster when moving or transferring the eggs. Be very careful not to expose the eggs to open air. They are very delicate at this stage.
The survival of the eggs depends greatly on the cleanliness of the egg chamber. Every day I will check to make sure that there isn’t too much detruis being sucked into the tumbler. Give it a gentle shake or direct the output of a powerhead into the tumbler for a few moments to blow away the unwanted waste. I have experimented with prefilters but found that they just reduce the flow too quickly.
Another important thing to remember is: don’t put any white or fungused eggs in the tumbler, usually the white or fuzzy eggs are unfertilized and they will rot and ruin the entire brood if left in the tumbler with viable eggs.
The eggs can be left in the tumbler until they are fully formed fry. I will usually remove them once their eggs sacs have been completely absorbed and they no longer look like a tasty treat for the inhabitants of the grow out tank.
I’m always interested in hearing about your modifications feel free to post them along with any question you may have.
2 Responses to “DIY Egg Tumbler”
- Kai on 14 Jul 2008 at 12:42 am #one of my ideas was to put another sheet of mesh on the other end of the coupling on the bottom to keep most debris away from the eggs
- Marcel on 15 Jul 2008 at 2:53 pm #That’s a great idea Kai! The daily build up of detruis was a bit of a pain to clear out of the tube.
Thanks for commenting!