Aquaponics 101 – Koi Jump

Picture this. You are standing in a pond. The water is about a 900mm deep. You are busy cornering a group of innocent little Koi fish. The next minute a 5kg slab of meat launches itself out of the water and smacks you in the chest at about 100km/h. Your assistants roll about laughing as you pick yourself up.

Koi jump and they jump high, fast and accurately, a lot like mini dolphins. No matter how placid and laid back they look, when cornered, they can take off like a bullet, a very heavy, wet bullet. We captured and transported the Koi to the commercial aquaponic site today, amidst much laughing and revelry. I’ll spare you the messy details and just show you the pond where we did battle and two photographs of the captured fish.




The blue container that I photographed them in, is 70cm x 40 cm, just to give you some sense of scale. The larger of these Koi are over 40cm and the smaller ones are 30cm plus!!

I quickly put together a pond with a bio-filter, and hope that this will be enough for a few days. They are in a 7800L pond and the sump (sunken) holds another 5000L of water, so they should be OK until we get some grow beds going. Here is a photo of the bio-filter and two of what the stand pipe in the middle of the pond looks like.




The way a standpipe works, is that the height of the inner pipe determines the height of the water in the tank. The outer pipe is a sleeve to firstly keep baby fish from going down the middle pipe, but more importantly, to suck water from the bottom of the tank. At the bottom of the large, outer pipe, slots are cut with an angle-grinder. Water and solids flows through these slots, up the gap between the two pipes and then down the inner pipe. Magic, and very low-tech.

Here is an image of the hatchery dam. The large red male Tilapia can be clearly seen and the small plain fingerlings are those dark spots just below the surface.


There are literally hundreds of them. We have now stopped feeding pelletised food completely and are trying them out with a range of kitchen peelings. So far they seem to like pawpaw and carrot peels but don’t like any citrus.

Enough for now.



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