What is rice fish farming? Rice fish farming raises fish in flooded rice fields so both crops share the same water. FAO says fish fertilize the rice, eat larvae and weeds, and stir the soil, while rice gives fish shade and food. Farmers often dig a deeper trench or pond as a refuge for the fish.
Key takeaway: Rice fish farming is an old Asian co-culture that FAO recognizes as a Globally Important Agricultural Heritage System in Zhejiang, China. It can cut pesticide and fertilizer use and add fish income, but it needs higher dikes, screens, a fish refuge and careful timing of field drainage, fertilizer and any pesticide.
| Element | Typical practice | Source |
|---|---|---|
| Water over field | 6–8 in (15–20 cm) | FAO, Culture of Fish in Rice Fields |
| Refuge depth | About 20 in (50 cm) below field level | FAO, Culture of Fish in Rice Fields |
| Center pit | 11–22 sq ft (1–2 m²) | FAO, IAA primer |
| Main fish | Grass carp, common carp, Nile tilapia, crucian carp | FAO, IAA primer |
| Fish yield | About 270–400 lb (120–180 kg) per acre (0.4 ha) | FAO GIAHS |
How Does Rice Fish Farming Work?
Fish and rice support each other in one field. FAO’s heritage profile says fish provide fertilizer to rice, regulate micro-climate, soften the soil, disturb the water and eat larvae and weeds, while rice provides shade and food for fish. A Han Dynasty clay plate about 2,000 years old shows a fish swimming from a pond into a rice field.
FAO’s integrated agriculture-aquaculture primer says rice fish farming in China dates back more than 1,700 years and reached more than 1 million ha (2.5 million acres) by 1986.
What Are the Benefits of Rice Fish Farming?
It adds food, income and natural pest control. FAO’s GIAHS profile lists food security, fish nutrition and income, reduced mosquitoes, biodiversity and less use of chemical fertilizers and pesticides. FAO says that although fish take some rice area, the system gives higher returns than rice monoculture because rice yield is higher and farmers sell fish.
- Fish eat stemborer and leaffolder insects, per the FAO primer.
- They also eat pathogens such as sheath blight floating in the water.
- Grass carp eat many paddy weeds, reducing other weed control.
How Do You Prepare a Field for Rice Fish Farming?
Modify the field first. FAO’s Culture of Fish in Rice Fields lists four changes: raise dike height, add weirs or screens to keep fish in and predators out, provide drains, and dig deeper areas as a fish refuge. A refuge can be trenches, a pit or sump, a pond, or a fish pen, and it also helps at harvest.
- Raise and strengthen the dikes (bunds).
- Screen inlets and outlets.
- Add a controllable drain.
- Dig trenches or a pond as a refuge.
The FAO primer says a trench-pit design, with a 11–22 sq ft (1–2 m²) center pit linked by trenches, raised rice yield by 10% and allowed one to two times as many fish as a traditional field. A larger trench-pond design raises and stabilizes both yields.
How Deep Should Water Be in Rice Fish Farming?
Keep the field flooded as deep as rice tolerates. FAO says most literature gives 6–8 in (15–20 cm) of standing water. With a refuge 20 in (50 cm) below field level, fish get an effective depth of 26–28 in (65–70 cm), which offers a cooler area when shallow field water warms to as high as 104°F (40°C).
For fish ponds linked to plant beds, see our pond aquaponics guide.
Which Fish Work Best for Rice Fish Farming?
Carp and tilapia dominate in China. The FAO primer names grass carp, common carp, Nile tilapia and crucian carp as the four main species for polyculture. It recommends grass carp and tilapia together making up about 70% of the stock, with common and crucian carp the remaining 30%. FAO’s heritage site in Zhejiang raises six native carp varieties.
- Compare species in our best fish for aquaponics guide.
- Read our tilapia aquaponics guide for tilapia needs.
How Do You Stock and Feed Fish in Rice Fields?
Acclimate fish, then feed. The FAO primer advises mixing paddy water into the transport container to even out temperature. It describes stocking fry 0.8–1.2 in (2–3 cm) long at 2–3 per 11 sq ft (1 m²), or fingerlings 3–4 in (8–10 cm) long at 2–3 per 108 sq ft (10 m²), a month after transplanting.
As fingerlings grow, FAO says daily green grass is needed so fish do not damage young rice; grass is fed in the pond, and rice bran in the paddy. See our aquaponics fish food guide for feed basics.
How Do You Protect Fish During Fertilizer and Pesticide Use?
Drain fish into the refuge first. The FAO primer says to slowly drain the paddy so fish return to the trench or pond, apply top-dressing fertilizer as the ridges nearly dry, then reflood two to four days later. In trench or pond fields, drain water into the refuge before pesticides, and use only chemicals not toxic to fish.
What is rice fish farming?
Raising fish in flooded rice fields so both crops share water, as FAO describes.
How much fish can rice fish farming produce?
FAO reports about 270–400 lb (120–180 kg) per acre (0.4 ha) at its China heritage site.
Which fish are used in rice fish farming?
Grass carp, common carp, Nile tilapia and crucian carp, per FAO.
Does rice fish farming increase rice yield?
FAO says a trench-pit design raised rice yield by 10%.
Why is a fish refuge needed?
It holds fish when field water dries up or is too shallow, and aids harvest.
Sources
- Food and Agriculture Organization. Rice Fish Culture, China (GIAHS).
- Food and Agriculture Organization. Integrated agriculture-aquaculture: Rice-fish systems in China.
- Halwart and Gupta, FAO and WorldFish Center. Culture of Fish in Rice Fields.
- Photo credits (Wikimedia Commons, edited with titles): Fish Ponds and Rice Fields, Lower Guadalquivir River by NASA (Public domain); Pond-edge plants at Achamore Garden – geograph.org.uk – 5446824 by M J Richardson (CC BY-SA 2.0); Fish Feed Pellets by Narek75 (CC BY-SA 4.0); Deep Cut Gardens Koi Pond by FossilDS (CC0)