Two Letters Re: Ponds, Aquiculture, and Pond Predators

Hey James,
I have been pondering (pun intended) bioponics (AKA aquaponics) for a couple of years now.  A seminal site,, describes bioponics as “A simple and innovative system of food production combining aquaculture and hydroponic growing techniques without expensive equipment” or the use of mineral nutrient salts.
Here’s how it works.  Water from the fish tank is pumped to grow beds.  In addition to crops, the grow beds contain naturally produced bacteria.  The bacteria breaks down the fish waste thus cleaning the water.  The plants feed on the nitrogen produced by the bacteria.  Finally, the water is drained back to the fish tank.
There is a reasonable amount of info on the net about bioponics including plans for simplified hobby systems, which would allow you to get your feet wet before taking the plunge (puns likewise intended).  I would suggest, however, searching on aquaponics instead of bioponics. Best Regards, – d’Heat



Dear Jim:
In response to the Pond, Aquaculture, and Pond Predators letter from The Wanderer, I suggest the first thing to read on the subject of fish farming for food for survivalists is this timeless article: and
In response to the questions posed, briefly:
1). What type of fish replenish the most rapidly while offering a genuine nutrition?
The “ugly” fish, meaning types of catfish and carp, tend to be the easier and better to fish farm. Most “game” fish are messy. They eat a lot and create a lot of waste, thus you either must be flushing in fresh water regularly, or you can’t expect much density or production.
I’m sure most people think right away of raising trout , and you can do it, just realize the costs and limitations. For those of you on the East US coast, see this site.
Do a search, and find one near you, in your state or region.
2). What types of fish are compatible or necessary to keep a full circle eco-system continuing?
Catfish, carp, koi, goldfish, are the easiest, though I was told goldfish eat Koi eggs. So do some research on which ones cohabitate well. Contact a fish farm supplier in your state and see what other varieties are legal and would work well in your area. You can mail order fish, they ship them in hyper oxygenated water boxes.
IMHO, it’s the bottom feeders you want, and they tend to be net-benefit fish, that they make the water cleaner rather than dirtier. Still, you need some new water. Commercially, I believe they try and flush 5% of the water each day, taking from the bottom if possible as the toxins tend to be heavier and settle. It’s those nitrates you want out. Ideally, in a closed system, you would want to pump (by windmill or whatever means) water from the pond over a little wetland area with nutrient absorbing plants to help get out the fish wastes. Water hyacinth, a free floating plant, is especially good at this. You should also aerate and agitate it, and most backyard ponds do this by waterfalls. The best system for this, IMHO, which tries to work with nature, instead of against it with chemicals, is Now remember, this is more of a yuppie thing, not raw survivalism, and yes the stuff can get pricy.
Also note – the nitrates you flush out of our fish pond, can make great irrigation fertilizer. Suck gently from the bottom, use a gravity system if possible.
3). How many fish can you support per cubic yard of water?
That depends. There is an expensive mini-commercial system where you can raise 50 pounds of fish in only 400 gallons – but keep in mind the costs involved in doing so. Again, how fresh, and how aerated are you keeping the water, that’s the key.
4). Should food be introduced into the water until the young are established?
Food should be introduced all the time if you want any reasonable production in a smaller pond. If fish aren’t fed, they don’t grow very fast. I like the idea of having a worm farm for garage, and then feed the worms to the fish. Also remember, there is an optimal harvest size for each fish, and it’s usually short of “full grown”. Fisherman know that it usually isn’t the trophy lunker that actually makes the good tasting shore lunch.
5). What predators, (i.e.- ground/air living) would be a potential food source or havoc on your newly established “ecosystem”.
Raccoons if your pond is very small. Birds – blue herons in particular. Many of the birds that eat fish of some size are of course protected species, so if you have a real problem, consider a bird net over the pond. – Rourke