Growing fish in the backyard

Many of us are looking for ways to produce organic food in our homes. There was a time we had an aquaponics system in our backyard, and I thought it would be a good idea to talk about it again, despite the fact that our system failed and we sold it.

Aquaponics is a way of growing fish and organic vegetables in one system. The way we set ours up was with two grow beds on top of a 3000 litre (792 gallons) fish tank. We kept silver perch in our pond, they're an Australian native freshwater fish. We had our system from March 2007 until the end of February 2008.

We had our tanks custom made by a local tank maker but they are equally effective using recycled materials of sufficient size. Hanno rigged up all the plumbing and attached the bubblers and underwater pump. Our electricity bill barely registered the pump usage, I think over the course of a year it cost us about $80 to run it. We used rainwater that we had stored in our backyard tank to fill the fish tank.

We grew a variety of vegetables, including some decent pink brandywine tomatoes, chard, celery, parsley, beans, watercress, capsicums (peppers) and chilli. The taste was good and we couldn't tell the aquaponics produce from that in the garden. Of course we still kept our soil vegetable garden but having the fish and vegetable combo was a great project for us and it was very interesting to see what we could grow.

I won't go into aquaponics in depth, please look at my aquaponics posts to see what we did, or go to Backyard Aquaponics. There are a few good photos there of Joel's system and a very good forum where you can ask questions and see what people are doing all round the world. The site is an Australian one but they have a lot of members in the northern hemisphere, including some members with hothouse aquaponics in snowbound America.

Basically, aquaponics is a system that pumps the water the fish have been swimming in up to the vegetables growing in tanks above. The fish waste in the water fertilises the vegetables, the gravel and microbes in the grow beds help purify the water and then it falls back into the fish tank as clean water. Over time the system matures with natural elements helping the fish and vegetables grow and generally, it will take about 12 - 18 months from fingerling to plate sized fish.

Our system failed because we didn't understand the effect sun has on water. It caused algae to grow, which consumed oxygen in the water and when the fish didn't have enough dissolved oxygen in the water, they died. It was heartbreaking to see it happen. We didn't know why it was happening and every effort we made to save the fish was in vain. That was the second time our fish died, the first time we didn't know why, we think it was some poison, maybe someone in the neighbourhood had sprayed. Nevertheless, the second time it happened, we decided it wasn't for us, Hanno had to do a lot of work whenever anything went wrong, so we sold our system. I have to say though, that if we didn't have a very productive soil garden, we would have persevered with aquaponics, and by now would have been happily eating the fish on a regular basis.

I think aquaponics is a good way of growing food if you have the time and strength to put into it. You need to learn a lot about how everything works together, and as it's a fairly new way of growing food, sometimes there are no answers, but it's an interesting hobby and if you get it right, a very good way to produce vegetables and fish in a small space.

Unstuff writes about the failing economy and what she has discovered in the past year. It's worth a read.