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  1. #1
    Moderator badflash's Avatar
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    Air Powered Egg Tumbler

    I've built several egg tumblers in the last year to hatch tilapia eggs. This one is the best so far and the easiest to control. It is made from scrap parts I had laying around, but you could buy everything you need for under $20.

    If you want lots of tilapia fry, the best thing is to watch for females holding eggs, then strip the eggs from them about 2 days after they start brooding. The wait is to see if they are fertile. They swallow them if they aren't. Stripping is easy once you've done it a few times. Catch the female in a fine mesh net so any eggs she spits out are recovered. I put 2" PVC pipes in my breeding tanks and just net a female tube & all. I take a quart measuring cup and fill it with aquarium water. I hold the female gently, but firmly in one hand while holding her lower lip down with my thumb. Dip her head down in the cup about 10 times, then check to see if all the eggs are gone. Repeat as needed and return her to the tank.

    Stripping eggs is actually better for the female than allowing her to brood. They don't eat while brooding.

    I had some 2" and 1.5" PVC piping left over from a project, and old sponge filter, missing the sponge, some aquaculture screen tubing, some plastic screen wire, and my trusty hot glue gun.

    Here is the base:


    It is a 1.25" threaded PVC pipe fitting designed for hanging pipes in closets for hangers. I hot glued a short piece of some 2" aquaculture screen tubing I use. It is designed to fit snugly over 2" PVC pipe. I hot-glued it in place.

    I had an old aquarium siphon tube laying around. I removed the cap that connected it to the siphon tubing. I found that 1.5" PVC pipe would fit inside very snugly.


    Here is a look at the inside. I beveled the top of the 1.5" pipe with a dremel so that it made a smooth transition. I didn't want a place for the eggs to land and get stuck.


    Here are the rest of the parts:


    The top center item is the top of a sponge filter. It has a fitting to hold an air stone (center) and accept an air line. Lower right is some simple plastic window screening cut to size and formed over the clear siphon tube shown previously. Lower left is a short piece of 2" PVC pipe.

    The screen goes over the end with the 1.5" beveled PVC pipe in it, then the 2" PVC pipe holds it in place.


    The whole thing goes together with the sponge filter part looking like this:


    The air hose provides just enough snugness so the air bubble can be adjusted but does not slip and does not pinch the air hose.

    Here is a shot of the finished product in service. I'll post a youtube of it in action shortly.
    The best fertilizer is the farmer's shadow

  2. #2
    Moderator badflash's Avatar
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    Re: Air Powered Egg Tumbler

    Here is the youtube:
    [video:2tpp857s]http://www.youtube.com/watch?v=0geugaTqAkI [/video:2tpp857s]
    Once the fry start swimming on their own, they just get carried by the bubbles into the tank. Clean well between uses.
    The best fertilizer is the farmer's shadow

  3. #3
    Moderator jackalope's Avatar
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    Re: Air Powered Egg Tumbler

    I'm not sure I get the whole picture, but I think the "updraft" of the water, created by the air-stone in the center column, is causing the eggs to be bounced around (for what purpose I'm not sure ?).
    As the fry hatch, I would guess they are drawn up thru the center column, past the air-stone to the "get-away hatch" at the top of the column. Is that pretty much how it works? If so, it's ingenious!

    Now a question; why do the eggs need to be "jiggled," is it to keep them from being rotted by just sitting around on the floor of the tank?
    I use the Linux Operating System ...... Free as in beer!
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    Aquaponics - food'n'fish at your doorstep

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  4. #4
    Moderator badflash's Avatar
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    Re: Air Powered Egg Tumbler

    Tilapia are mouth brooders and have evolved an elaborate way of spawning and protecting their young. Tilapia have an elaborate mating ritual, then they spawn by the female laying here eggs on a flat surface. The eggs are much heavier than water and sink to allow the male to fertilize them and to allow the female to retrieve them and keep them in her mouth until they are ready to go off on their own.

    Check this youtube to see what spawning looks like:
    [video:3v0myk6n]http://www.youtube.com/watch?v=Vta0fPnEMwU [/video:3v0myk6n]

    The female constantly agitates the eggs in her mouth and keeps water flowing across them. She can tell bad eggs by taste and feel and swallows them. Once the babies hatch they have a huge egg sack and are still heavier than water, so until the sack is used up some, they stay in the tumbler. Without the constant tumbling, they don't become fry, or become very deformed ones. Once the sack is about gone it is up to the bubble chute and into the tank.

    Here is what freshly hatched fry look like:
    [video:3v0myk6n]http://www.youtube.com/watch?v=F8cYWKC6m2o [/video:3v0myk6n]

    The yolk sacks are clearly visible.

    The fry must be separated from the adults as they will snack on any fry that get too close.
    The best fertilizer is the farmer's shadow

  5. #5
    Moderator jackalope's Avatar
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    Re: Air Powered Egg Tumbler

    Nice vids badflash!
    I use the Linux Operating System ...... Free as in beer!
    You're never too old to learn something
    Aquaponics - food'n'fish at your doorstep

    Helena, Montana - Home of the Northernmost Monument to the Confederacy

  6. #6
    Moderator badflash's Avatar
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    Re: Air Powered Egg Tumbler

    This shows how fast the eggs develop. This is one day later:
    [video:2dpp9qdq]http://www.youtube.com/watch?v=EQ13JPYZTS4 [/video:2dpp9qdq]
    The best fertilizer is the farmer's shadow

  7. #7
    Moderator jackalope's Avatar
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    Re: Air Powered Egg Tumbler

    I use the Linux Operating System ...... Free as in beer!
    You're never too old to learn something
    Aquaponics - food'n'fish at your doorstep

    Helena, Montana - Home of the Northernmost Monument to the Confederacy

  8. #8
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    Re: Air Powered Egg Tumbler

    Good stuff! I am impressed! How long have you been breeding Tilapia? Do you have any formal education in it? How many fry do you produce annually?

  9. #9
    Moderator badflash's Avatar
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    Re: Air Powered Egg Tumbler

    I've been breeding tilapia for a little over a year. No schooling other than reading and doing. I've had aquariums since I was 12. My tilapia mentor is Mike Sipe and he gave me some hands on training last year. I have a working contract with him to raise his gene line. Mike pretty much invented the tilapia industry in the USA, but got little benefit from it. Nearly all the red tilapia breeds are descended from his fish.

    I can produce around 1000 fry a week. Once my greenhouse goes up, I'll have far more capability. My market is primarily home breeders that are looking for small numbers of fry.
    The best fertilizer is the farmer's shadow

  10. #10
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    Re: Air Powered Egg Tumbler

    I have read a lot of Mike's stuff. I have bought from Miami-Aquaculture and they sell his his fish. What do you think of the Pennyfish? Which fish do you breed?

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