Aquaponics has taken off in recent years among farmers seeking to boost their production but the practice has surprisingly ancient roots. Almost 1,000 years ago, Mesoamericans in the Mexico Valley bred fish and grew vegetables using what they referred to as chinampa: small plots of farmland floating on shallow lake beds. Considered the first form of aquaponics for agricultural use, chinampa were clearly effective as they remain in use today.
Aquaponics (the word is a portmanteau of “aquaculture” and “hydroponics”) is a closed-loop farming system in which fish and plants co-exist symbiotically. The fish excrete waste into the water, where bacteria break it down into nutrients that are absorbed by the plants hydroponically. This process purifies the water, doing away with the need to change it or to clean the tank.
Aquaponics is highly water efficient; with no evaporation or runoff, it can reduce water consumption by 90 percent compared to traditional agriculture. It also requires relatively little space, making it perfect for a land-scarce country like Singapore.
Some argue though that aquaponics could be greatly expanded to increase Singapore’s agricultural productivity – the city-state imports over 90 percent of its food – and also address the depletion of global fish stocks.
Researchers are experimenting with aquaponics in an effort to improve farming practices in Singapore and find alternative sources of food. Temasek Foundation Innovates, part of the philanthropic arm of Temasek Holdings, is researching ways to grow Soon Hock fish using shallow tanks alongside vegetables and herbs. The project is funded by Temasek Foundation’s Singapore Millennium Foundation Grant, and is led by an aquaculture expert, Professor Lam Toong Jin. Also known as marbled goby (Oxyeleotris marmorata), Soon Hock is a delicacy served in Chinese restaurants and is loved for its fresh and sweet taste.
Aquaponics at home
Establishing a working aquaponics setup requires some finesse, as the requirements of two ecosystems need to be in balance. Making a mistake with your aquarium can result in sickly fish, which in turn will affect plant growth. For example, excited beginners could rear too many fish in their tanks, leading to high nitrate levels that are harmful to the fish. Furthermore, certain plants, such as cherry tomatoes, do not like too much nitrogen, as it will encourage the growth of foliage instead of the flowers needed to produce fruit.
But there are aquaponics experts out there who are willing to share their knowledge through workshops and courses. Some have created home aquaponics kits to save you the time and hassle of making your own system.
Ecoponics director Ivan Sei runs an aquaponics programme for schools. The former primary school teach started using aquaponics in his science lessons to make his classes more fun and less theoretical. “Students get to learn about plant systems, parts of fish and ecosystems,” he says.
Sei sells introductory aquaponic systems for homes and schools. Priced at S$688 each, they comprise grow lights, a vegetable grow bed, a biokit to filter and redirect the fish waste, and a large fish tank. The set comes with an aquaponics textbook written for primary school students. Users begin their aquaponics journey by cultivating Kang Kong, an easy and fast-growing leafy vegetable popular in most Southeast Asian cuisines.
He advises beginners to start off with ornamental fish that are easy to rear and small enough for a basic setup. “Goldfish, guppies and tetras are good,” he says.
Another outfit that stocks its own aquaponic kits is Cloud Aquaponics. The company designs and builds aquaponics systems for those with no experience at all in gardening or aquaculture. It retails kits from S$160 for a small table-top setup to S$388 for a larger kit suitable for a balcony or garden.
A delicate balance
Growing your own vegetables and fish for food in an integrated system may sound exciting but can take some persistence. “Perhaps one of the biggest challenges is not knowing what works for your own setup. For this, it requires trial and error until you find a great solution that works for you,” says Sei.
Former aquaponics consultant Ethan Phang concurs. “My advice for beginners is to start small and to grow as many crops as possible, and try to pair the different types of crops with different fish, and in different landscapes, whether it is indoor or outdoor,” he says.
Phang realised early in his aquaponics pursuit that nitrates alone are insufficient for healthy plant growth. “The first wrong message that aquaponic systems marketers put out is that there is no need for fertilisers at all,” he says. “Nitrates are just one of the nine nutrients and minerals to sustain plant growth. You will still need to give your crop fertilisers from external sources.”
Phosphorous and potassium are needed for strong root growth and to induce flowering, while trace elements such as magnesium and calcium can help to deliver a healthy crop, too. “Artificial lighting is also key in indoor aquaponics,” he says.
A self-confessed “fish guy”, Phang has always had a passion for aquaculture. He dived into aquaponics a decade ago and his projects has designed and managed aquaponics farms in Bentong, near Malaysia’s Genting Highlands, and in Taiwan. He believes hobbyists who have aquaculture and aquascaping backgrounds are well-equipped to succeed at aquaponics.
“Fundamentally, their principles are the same – both disciplines seek to maximise the health of the fish and the plants in a single aquatic environment, ” he says.
Although he’s now a sales consultant for a software company, Phang is still passionate about aquaponics; the garden of his parents’ home in Kuala Lumpur features his own aquaponics system.
“It was designed more for an experimental purpose as I have a fish pond in the garden. And one of the key issues is that the fish pond is costly to maintain, as you have to change the water and you have to find a way to reprocess the fish waste. The aquaponics system was to cut down the maintenance and to conserve water,” he says.
Phang has since grown cabbage, basil and bittergourd in the 100 square foot aquaponics system. He’s tried to grow tilapia for consumption – it’s a good species for beginners, he says, as they are “very hardy” – but has been thwarted by an unlikely source: his mother.
“We wanted to eat the tilapia in the pond but my mom was against that,” he says, laughing. “She thinks the fish are her pets now.”