Fish are Friends

I bet you never thought goldfish could be the missing link to sustainable food production. Well, you better take a second look at these humble little guys, because if you’ve ever wanted to grow your own food—without a lot of space, soil, or chemical fertilizers—then a goldfish just might be your new best friend (along with several million bacterial ‘acquaintances’).  This is the beauty of aquaponics.

A student checks out goldfish in an aquaponics system built by USC Grad student Ryan Lesniewski.

A student checks out goldfish in an aquaponics system built by USC Grad student Ryan Lesniewski.

First things first: aquaponics is NOT hydroponics. Hydroponics, while very efficient at growing plants without soil, relies on a sterile environment and a lot of energy input and external regulation, especially in the form of synthetic chemical fertilizers that are usually made from petroleum. Therefore, most hydroponic endeavors, while innovative, are resource intensive and not sustainable. Aquaponics, on the other hand, mimics natural biological systems to create a thriving ecosystem that eliminates the need for synthetic fertilizers, while still maximizing efficiency of plant growth. You don’t need any soil, and you need very little space. It all comes back to the fish and the bacteria. While backyard aquaponics systems typically use feeder fish like goldfish, commercial systems tend to use marketable fish like Tilapia, which they can harvest and sell along with their food crops, resulting in an even more lucrative, yet still sustainable, food production system.

The basics of an aquaponics system go like this: 1) the fish create waste that bacteria in the water consume, which releases valuable nutrients like nitrogen and phosphorus; 2) this nutrient rich water is ‘fed’ to plant roots to nourish the plants and help them grow; 3) by removing these nutrients from the water, the plants have ‘purified’ the water which is then re-circulated back to the fish.  The water is naturally purified, and the plants are naturally fed, in this fairly closed system. The bacteria do the essential dirty work in between. The only input needed is fish food, which you typically have to buy. However, even this part of the system may soon become completely sustainable, because biologists Ken Nielson and Radu Popa of River Road Research are developing fish feed as one by-product of their black soldier fly project (discussed in my last post).

The basic biological process utilized by aquaponics.

The basic biological process utilized by aquaponics.

Grow Your Own

David Rosenstein of EVOFarm, based in Santa Monica, explained the biological processes behind aquaponics in a lecture as part of the Future of Food program I attended on Catalina Island this past week. David, an unimposing young entrepreneur with a passion for sustainable food, founded EVOFarm as a way to fight back against our current chemical laden, diesel powered, polluted and corrupt industrial-agricultural complex.

Through years of tinkering and tireless perfection, David and his team have created aquaponics systems that successfully provide abundant harvests at all scales, from small backyard units for families, to larger scale systems for schools and for commercial sale of crops. Using aquaponics, you can harvest crops (like lettuces, kale, tomatoes, chard, spring onions, etc.) up to ten times per year, and produce anywhere from six to thirty times the amount of food per acre that you could reasonably harvest from a soil based system. Revolutionary! David estimates that the dollar value of this food per acre is over 1 million dollars, which would be unheard of in a soil system.

David Rosenstein of EVOFarm talks about the wonders of aquaponics and shows off one of his 'NanoFarm' model systems.

David Rosenstein of EVOFarm talks about the wonders of aquaponics and shows off one of his ‘NanoFarm’ model systems.

The yields from aquaponics aren’t just remarkably higher, but they are created without the use of harmful synthetic fertilizers, are very water efficient (water is continually recycled in the system, with minimal evaporation), can exceed organic standards, taste amazing, and result in local food security. You could literally have an aquaponics system in every backyard, as well as larger community-run systems. This would help reduce the number of ‘food miles’ of the fresh fruits and vegetables that we eat, lowering our impact on climate change as well as our reliance on industrial agriculture. Plus, it’s a fun hobby!

Rome wasn’t built in a day…but this aquaponics system was!

The students successfully built a small-scale aquaponics system in a single afternoon. Pretty impressive! The bottom tank is where the fish live, while the top is where the plants will grow.

The students (with some help from David and Ryan) successfully built a small-scale aquaponics system in a single afternoon. Pretty impressive! The bottom tank is where the fish live, while the top is where the plants will grow.

It’s actually super easy to build your own aquaponics system—and that’s just what we did (well, I mainly watched the students build it while I tagged along to take pictures). David, along with USC graduate student Ryan Lesniewski, showed us that with a few basic materials and a small investment, you can have your system up and running in a day, and be ready to plant all the crazy heirloom seeds you want by the end of the week.

After you get water into the system, you add some compost tea (aka liquid worm poo) to help grow the beneficial bacteria, which sets the biological basis for the system. Then you can add your fish, place your plants on top, and watch nature take its course. You need to monitor the water level and quality fairly regularly, but other than that the system is very low maintenance day-to-day (though if you like tinkering, there are myriad variables you can mess around with, like nutrient sources, quantities, water flow rates, etc.).

Ryan sifts the compost tea--nutrient rich worm castings that will be used to jumpstart beneficial bacterial growth in the aquaponics system.

Ryan sifts the compost tea–nutrient rich worm castings that will be used to jumpstart beneficial bacterial growth in the aquaponics system.

Compost tea under a microscope, full of bacteria, protists, and other microorganisms that will help cycle nutrients and keep the system healthy.

Compost tea under a microscope, full of bacteria, protists, and other microorganisms that will help cycle nutrients and keep the system healthy.

In fact, Ryan has been experimenting with these types of variables as part of his PhD research, which is focused on the development of aquaponics. He has become a self-made expert in a novel field where there aren’t really any experts yet. By growing seedlings in his closet and building aquaponics test systems on his tiny downtown L.A. balcony, Ryan has already learned a lot about the ins and outs of growing plants sans soil, knowledge that he is applying to the larger-scale systems he experiments with out on Catalina.

Meanwhile, David has been designing eye-pleasing backyard vertical aquaponics systems for local distribution, perfectly sized for backyard patios and balconies. His real dream, though, is to establish large-scale aquaponics farms to grow food for commercial sale, and revolutionize (there’s that word again!) the agricultural industry.

Aquaponics can be used at commercial scales to sustainably harvest plants at fish with very high efficiency.

Aquaponics can be used at commercial scales to sustainably harvest plants at fish with very high efficiency.

If you have a passion for growing (or eating) healthy, fresh, mouth-wateringly good food, than you have a vested interest in the growth of aquaponics. I know that I’m a convert, and can’t wait to help out with future projects like these that engage people in growing their own food to save money and build food security—and hopefully have fun!

Replacing the vertical column. Nutrient rich water is pumped from the fish tank at the bottom of the system to the top of the columns, where it can trickle down and feed plant roots on its way back to the fish tank.

Replacing the vertical column. Nutrient rich water is pumped from the fish tank at the bottom of the system to the top of the columns, where it can trickle down and feed plant roots on its way back to the fish tank.

A student places seedlings along a substrate column that will be hung vertically and connected to the aquaponics system.

A student places broccoli-kale and heirloom tomato seedlings along a substrate column that will be hung vertically and connected to the aquaponics system.

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Posted on March 22, 2014, in Food news, Food politics and tagged , , , , , . Bookmark the permalink. 5 Comments.

  1. I’ll be setting up my first aquaponics system in my room this summer! I’m really excited to start learning all about this!

    • That’s great! Thanks for your comment. I hope I can set my own system up soon too. I’d love to hear how it turns out! A food revolution is brewing…one small fish tank at a time. 🙂

  2. Great post Dr. K! Thanks for coming out with us last week 🙂

  1. Pingback: Reaping the Tasty Benefits of Organic Gardening | doctor vegan

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