Aquaponic Farming: How to Think About Running It as a Small Farm

Aquaponic farming is aquaponics run as production: fish and plants raised together to sell, not to demonstrate. The system looks like a backyard one at larger scale, but the question changes from “does it work?” to “does it pay?”, and the honest answer depends on three things: a design sized to its feed rate, a market that pays well for fresh produce or fish, and a climate or budget that keeps energy costs under control.

This guide is for someone weighing the jump from hobby to a bigger backyard plot, a small farm or a business. It leans on university extension work: the SRAC 454 fact sheet by Rakocy, Masser and Losordo on the University of the Virgin Islands (UVI) system, Clemson’s system layout guide, and the 2022 Recirculating Farms survey of US aquaponic farms. If you are still learning the basics, start with what is aquaponics.

What Aquaponic Farming Is

An aquaponic farm uses the same loop as any aquaponics system: fish waste is converted by bacteria into nitrate, and plants take the nitrate up and clean the water before it returns to the fish. SRAC 454 puts the essential parts at five: a fish tank, a solids removal component, a biofilter, a hydroponic component and a sump. What changes on a farm is how those parts are sized, backed up and paid for.

Hobby vs Farm Scale

A hobby system can run on whatever tank you had and stay cheap even if half the lettuce bolts. A farm cannot. The survey’s top problem, named by 19 respondents, was system management and design, which covers keeping pH and temperature in range, getting the ratio of fish to plants right and maintaining equipment. In practice that means a farm needs measured feed input, planned harvest dates, spare pumps and a written routine for testing the water.

It also means the work stops being a weekend. The survey describes a field where growers mostly teach each other, and where training is itself a source of income: the four most commonly sold products and services were produce, training and education, food fish and microgreens.

Fish and Plants as Two Crops

Every aquaponic farm sells two crops that behave differently. Plants pay faster: SRAC 454 notes lettuce reaches market size in 3 to 4 weeks in the system, while a tilapia tank in the UVI design has a 24 week growing period. The survey showed the same split in the books: vegetables are the principal product sold, and among the profitable farms that reported revenue, plant sales averaged 483,585 dollars a year against 77,000 dollars for fish. Only seven of the 14 profitable farms answered that question, so read the figures as a pattern, not a forecast.

The fish are still the engine. They supply the nutrients, so their feed rate caps how many plants you can grow, a point we return to under sizing.

The Three Farm Designs

Every aquaponic farm grows its plants in one of three ways: media beds, raft (deep water culture) channels or nutrient film technique (NFT) troughs. Clemson’s layout guide describes all three, and SRAC 454 explains how each changes the farm’s water volume and feed rate. If you want the build details of the winner, read our dedicated guide to the aquaponic raft system.

Media Beds

Media beds are trays of gravel or clay pebbles that flood and drain with a bell siphon. Clemson calls the media bed “probably the most diverse plant system that is practical for an aquaponics unit,” because it lets fast-growing lettuce grow next to long-growing, fruit-bearing tomatoes. SRAC 454 warns that granular media can clog, and that serious clogging from organic overload can make a bed produce ammonia instead of removing it. Media beds suit small and mixed-crop farms. For the hobby side of the design, see our guide to aquaponics grow beds.

Raft (Deep Water Culture)

Raft systems float polystyrene sheets on channels of water. Clemson describes the trough as six to eight inches deep and usually four to eight feet wide, and says it suits fast-growing plants with a short life that are harvested whole. SRAC 454 calls a raft subsystem “ideal for the cultivation of leafy green and other types of vegetables” and describes the UVI channels as 100 feet long by 4 feet wide, holding 12 inches of water. Because most of the system’s water volume sits in the channels, rafts also buffer nutrient swings. It is the layout of the UVI commercial design.

NFT

NFT runs a thin film of water down narrow troughs. SRAC 454 says it has been used successfully in aquaponic systems, but that solids must be removed so they do not kill the roots, and that a break in water flow “can lead quickly to wilting and death.” Clemson adds that the usual small tubing clogs with bacterial growth, so aquaponic NFT uses larger diameter pipe, 4 or 6 inches. That makes NFT less forgiving than rafts when a pump fails.

Planning a Small Aquaponic Farm

Plan a farm backward from what you can sell. SRAC 454 gives two design routes, starting from a fish target or a plant target, and both end at the same ratio between fish feed and plant area.

Site and Climate

Climate sets the energy bill. SRAC 454 says an outdoor tropical system would cost less to build and run than a controlled-environment greenhouse in a temperate climate, and that winter growth in temperate greenhouses slows substantially when solar radiation is low. It adds that supplemental lighting is generally not cost effective unless you have an inexpensive energy source. The survey tells the same story about location: more than half of the farms it counted were rural and about a quarter urban, so land is not the only limit. Our guide to the aquaponics greenhouse covers heating, cooling and ventilation.

Sizing by Feed Rate

The number that sizes the farm is the feeding rate ratio: grams of fish feed per day per square meter of plant area. SRAC 454 gives 60 to 100 g/m²/day for raft culture and says to use the low end for small plants such as Bibb lettuce and the high end for larger plants such as romaine. Gravel and NFT systems hold much less water, so SRAC says their ratio should be about 25% of the raft ratio. Fish are stocked to a final density of 0.5 pound per gallon, and feed is the sum of what that biomass eats.

SRAC’s worked example shows how the pieces fit when a grower needs 500 pounds of live tilapia a week:

SRAC advises against changing the standard design much, because changes “often lead to unintended consequences.” If space is the limit, scale the design down and keep the water flow rate scaled with it.

Water, Power and Backup

Water needs are small once a system is running: SRAC 454 notes daily exchange can stay under 2% in closed recirculating systems. The water must be right, though. SRAC says municipal water should not be used unless it is dechlorinated, and that surface water should not be used. Power is the real risk. The UVI system keeps dissolved oxygen near 80% saturation (6 to 7 mg/L) with a diffuser every 4 feet along the raft channels, so a pump or blower failure is an emergency. Plan standby power for the pump and aeration, a second air pump, and alarms before you stock a single fish. Our aquaponics pump guide covers sizing.

Which Fish and Crops Pay

Choose the crops by income per unit area per unit time, not by what is easiest to grow. That is SRAC 454’s stated criterion, and it points to herbs.

Fish

Tilapia is the most-used species in the survey, with ornamental fish such as koi and goldfish second. The UVI design is built around tilapia, and SRAC’s sale price in its budget was 2.50 dollars a pound. Tilapia also carries a permit risk in some states, so read our tilapia in aquaponics guide, which covers stocking, temperature and state rules, before you commit. If your state or climate rules tilapia out, our fish comparison shows the alternatives. Fish sales are modest: in the survey, most fish were sold directly to consumers or at restaurants, and some were not sold at all.

Leafy Greens and Herbs

SRAC 454 calls culinary herbs “the best choice” because they grow rapidly and command high prices. Its example: in experiments in the UVI commercial-scale system, basil production was 11,000 pounds a year valued at 110,000 dollars. Lettuce is the other staple, a crop that takes 3 to 4 weeks in the system and so has few pest problems, and UVI harvested 148 crops of lettuce in three years of continuous operation. Swiss chard, pak choi, Chinese cabbage, collard and watercress are listed as suitable. The survey agrees on the mix: lettuce, leafy greens and basil are the most common crops.

Fruiting Crops

Tomatoes, cucumbers, eggplant and okra earn much less per square foot. In the same UVI experiments, okra production was 6,400 pounds a year valued at 6,400 dollars. Fruiting crops also need 90 days or more and have more pest and disease problems. They suit media beds, as Clemson’s description of lettuce growing beside tomatoes shows. Treat them as an extra for a farm stand or restaurant customer, not the core of the business. SRAC also warns that pesticides are not allowed in a fish system, so pest control has to be non-chemical.

Costs and Profit: Why Many Aquaponic Farms Struggle

The recurring finding is that selling is harder than growing. In the Recirculating Farms survey, 79 respondents sold products, and 14 said they were profitable. The survey is voluntary and its sample is small, so do not read it as a statistic about the whole industry. It is still the best look we have at what working US growers report.

Startup

Building and infrastructure are the main hurdle. The survey reports an average building cost of 74,277 dollars, with the highest at 600,000 dollars, mostly paid from personal funds, and only 27% received any government grant. Its authors call the start-up costs “near fatal for some entrepreneurs.” Among the 14 profitable farms, the most common time to turn a profit was 1 to 3 years (57.1%), and 85% of them planned to expand within five years, against 40% of the farms that were not profitable.

Running Costs

The costs that do not go away are feed, power, labor and consumables. SRAC 454 notes the UVI system adds potassium hydroxide and calcium hydroxide, usually 500 to 1,000 grams of each, alternately several times a week to hold pH near 7.0, and it recommends buying a conductivity meter to watch dissolved nutrients. In the survey, costs (start-up, operating and energy) ranked among the top challenges, and a lack of skilled workers was also named.

Selling the Produce

SRAC 454 is blunt that economics depend on site and market. In its budget for tilapia and lettuce in the US Virgin Islands, six production units returned 185,248 dollars a year to risk and management at 2.50 dollars a pound for fish and 20 dollars a case for lettuce. The authors then add the caveat that matters: the Virgin Islands are a small niche market where more than 95% of vegetable supplies are imported, and the break-even prices for tilapia (1.47 dollars a pound) and lettuce (6.15 dollars a case) “do not compare favorably to commodity prices.” Their conclusion is that aquaponics can be profitable in niche markets. Basil is the exception because it is perishable and cannot be shipped far, but even there SRAC says a 66,000 pound a year budget is not realistic because the market cannot absorb it.

The practical lesson is to sell fresh and local: direct to consumers, restaurants and shops, at prices that commodity growers cannot match. Our guide to aquaponics vs hydroponics explains why a hydroponic farm without fish may be the cheaper route if you only want the vegetables.

Permits and Food Safety

Rules vary by state, county and city, and we are not going to guess at yours. The survey is clear that this is where many farms lose their margin. Selling produce and fish was the top regulatory roadblock, covering sales permits, food processing and food safety, and permits for importing and using fish species, especially non-native ones, came second. Among the 46 respondents who named required licenses, state aquaculture permits topped the list. One grower kept the operation small to avoid the certifications needed to sell at a more profitable level.

• Fish: contact your state fish and wildlife agency and agriculture department about aquaculture permits and any limits on species such as tilapia. We cover examples in our tilapia guide.
• Produce: ask your state agriculture department and county health office what applies to selling fresh produce, and whether washing and packing triggers extra rules.
• Zoning and building: the survey lists construction and zoning permits as a separate hurdle, and cities treat urban farms differently.
• Drug and chemical use: SRAC 454 says fish therapeutants should not be used because vegetables may absorb them, and that salt used for fish disease or nitrite is harmful to plants. Prevention through water quality is the whole strategy.

Write down who you spoke to and what they said. If a rule is unclear, ask for it in writing before you buy tanks.

Learning Before You Build

The survey says education is both a gap and an opportunity: growers often learn from one another because outside support is thin. Before you spend on a building, spend on learning. Our aquaponics courses page compares the options, and our aquaponics books page covers the full shelf. For farm planning, two books stand out, and the second is free to read online.

Planning the next step? See the aquaponic raft system guide, the aquaponics greenhouse page, or start from what is aquaponics.

Aquaponic Farming FAQ