Farming is central to life and the economy in Rwanda. However, limited land, unpredictable weather patterns, and increasing food demand are straining traditional agriculture. In response, some farmers and innovators are exploring aquaponics—a modern, soil-free farming method that uses significantly less water than conventional agriculture. Aquaponics combines aquaculture (fish farming) and hydroponics (growing plants in water) to create a closed-loop system. In this cycle, fish waste becomes a natural fertilizer for plants, while the plants help purify the water for the fish. ALSO READ: How bioengineer uses technology for water access This eco-friendly model saves space, conserves water, and can be set up in urban areas, on rooftops, or in small plots. How aquaponics works Alpha Mumarungu, a farm officer in Kayonza, believes aquaponics can enhance food and income security for smallholder farmers. She oversees a coupled aquaponics system, where all water remains within the loop and none is wasted. “The process begins with a fish tank and a hydroponic unit called deep water culture, where plants grow,” she explains. The fish tank water, rich in ammonia from fish waste, first passes through a solid filter that removes heavier waste. It then flows into a biofilter where nitrifying bacteria convert the ammonia into nitrates—nutrients the plants can absorb. ALSO READ: Kayonza's hi-tech farmer grows vegetables without using soil “Nitrates aren’t harmful to fish in small amounts, but if they build up, they can affect them,” Mumarungu notes. “Once the water is filtered, it moves into a sump tank and is pumped into a manifold, which directs it either back to the fish tank or to the hydroponic bed.” Affordability and Accessibility While aquaponics offers several benefits, Mumarungu acknowledges that affordability remains a barrier. “There are cost-saving options, like using crates or repurposing materials,” she says, “but technical components such as biofilters often rely on imported items.” One critical component is bio media—materials inside the filter that promote oxygenation and support bacteria growth. ALSO READ: Youth pursuing opportunities in cage fish farming “We need bio media to ensure enough oxygen reaches the bacteria, which is essential for the system to function properly,” she explains. A climate-smart alternative Agnes Niyonzima, a local agronomist and advocate for sustainable farming, sees aquaponics as a promising shift from labour-intensive, rain-dependent agriculture to a more climate-resilient model. “It allows families to grow high-quality vegetables and fish using fewer resources,” she says. “Aquaponics is about working with nature, not against it.” With the growing threat of climate change, Niyonzima adds, systems like aquaponics offer year-round production and reduced dependence on rainfall—aligning well with Rwanda’s agricultural innovation goals. Solange Uwituze, Deputy Director General at the Rwanda Agriculture and Animal Resources Development Board (RAB), says aquaponics is recognised as a sustainable model that combines aquaculture and hydroponics in a mutually beneficial way. However, she points out that Rwanda has yet to conduct official studies or pilot programs to assess its viability. “Aquaponics is still new here. Challenges include limited awareness among farmers, a lack of skilled technicians, and the absence of demonstration sites,” she explains. Despite these obstacles, Uwituze believes aquaponics holds promise for small-scale farmers by promoting organic food production, generating income, and encouraging resource efficiency. Currently, only three companies in Rwanda have attempted aquaponics. Good Social Farm Ltd, which relied on water from Gaharwa Lake, halted operations due to water quality issues. Ecobam Ltd, which plans to use Lake Muhazi, has received permits but has yet to launch. Only NjordFrey Ltd in Kayonza is actively running its aquaponics system. “This shows there is potential for scale,” Uwituze says, “but it will require trained technicians and investment to realize its full impact.”
