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Fishkeeping in a Cambodian Rice Field

Improving subsistence farmers diet with fish husbandry in Cambodia

How can a bunch of fish ponds make a real difference?

This summer I am travelling around South-East Asia, including Cambodia. In Cambodia I will be visiting some NGOs and voluntary aid projects. I meet with our main contact this week and most of the work is focused on people projects, teaching English, prison visits, drug addiction etc but they mentioned one project where they help rice farmers start fish husbandry projects. These projects are designed to help the local subsistence farmers grow on fish to adult size for increasing the protein component of their diet. Being interested in all forms of fish keeping I hope that when we travel to Cambodia I can visit the project or at least meet up with the team managing the project. It sounds like a fascinating and practical way to help some of the worlds poorest improve their diet and economic situation. It was mentioned that the project specifically looked at how fish farming can be combined with rice paddy fields. 

After hearing about this project I was greatly intrigued by how such a project would work in practice. After being frustrated that I couldn't find any details of the specific project in Cambodia I looked around for information about what the project would likely be. How it would work, what kind of ponds would be used and even which fish they could be using. I investigated two broad aspects. Firstly how fish culture projects can work across the world and secondly more directly how the current aquaculture scene in Cambodia. 

If you know nothing about aquaculture read this first to get an overview of Aquaculture HISTORY, DEFINITION, AND PURPOSES. I found a great example resource on fish farming from it is a great show case of how agencies can make significant differences. It also introduced the fish species tilapia which we will come back to later. Lots of the information is very similar to Amateur Fish Keeping from project Gutenberg. A classic book explaining the basics of fish husbandry, a skill thousands of years old. Through my research it has become clear that with just a little bit of investment and a good lump of information then Aquaculture can make a significant improvement in the lives of poor subsistence farmers across continents. 

Researching the current Cambodian Aquaculture scene I found this article "Aquaculture for the Poor in Cambodia" the most important summary from the worldfishcenter. Whilst this article on page 30 explained details about the historic situation. It seems that whilst the Cambodian people have fished freshwater fish for centuries the organisation of farming systems and natural fish stock preservation has been sporadic and possibly unsustainable. This situation is being exasperated by problems with the Mekong river water supply due to damming projects upstream. 

Who else likes fishing in rice fields?

It looks like a specific focus for many aid agencies is the construction of fish hatchery and larger growing on ponds. (See this YouTube example). The value of these projects for orphanages and similar communities is huge but need large investments in construction and training. I am much more interested in the lower input cost methods involving fish growing alongside rice crops. In the article "Aquaculture for the Poor in Cambodia" by Olivier Joffre, Yumiko Kura, Jharendu Pant and So Na summerise that. 

"Integrated rice–fish farming 
The term rice-fish culture is applied to the practice of raising fish within rice fields 
alternately or concurrently with rice production. In alternate systems, fish are 
raised between rice crops, while rice fields are flooded. In concurrent culture, 
fish are stocked while rice fields are cultivated, requiring a ditch around the rice 
plot as shelter for fish. Rice-fish culture is not yet common in Cambodia. The 
technique is recent, and is usually reliant on stocking of Pangasius catfish, silver 
barb (Barbonymus gonionotus), tilapia (Oreochromis niloticus), or common 
carp (Cyprinus carpio). Production is between 100 and 300 kg/ha for a stocking density of 0.03-0.45 individual/m2. Because irrigation is limited, fish are stocked in a pond connected to the rice field and the practice requires improvement of dike systems and the allocation of rice land for a ditch system." (Retrieved 14-02-12)

From this quote I wanted to look into some more detail about the species of fish suggested. 

Pangasius catfish
File:Pangasianodon Hypophthalmus 1.JPG
From Wiki commons
There are a number of species in this genus but the most common used for aquaculture appears to be Pangasius hypophthalmus or Pangasius bocourtii (which is sometimes sold in the UK as Basa or River Cobbler) and possibly the critically endangered Pangasianodon Gigas. The market value of these fish is outlined here and it appears clear that the fish has value as an exporting industry as the marine white fish supply continues to disappear. This could be an excellent fish for any collective aquaculture venture. Maybe for a village co operative or a large orphanage wanting to start making money. One of the most attractive aspects of this fish as an income generator is how just 1kg of feed will grow a 20g fingerling to a 1.5kg fish, this creates a very good invest return rate. However, I do not think this is suitable for the small scale rice paddy fields subsistence farmers because of the need to purchase fingerlings every year. Natural reproduction seems difficult/impossible in captivity unless you are willing to use hormones (far beyond the abilities of small scale set ups).

Silver barb (Barbonymus gonionotus
File:Barb gonio 080525 9625 ltn.jpg
From wiki commons
Silvery Barbs may be a good species for the use in rice paddy fields as they seem "to prefer standing water habitats instead of flowing waters". It is also reported to attain marketable size in just 3-4months. This means that farmers can turn around a profit in a much quicker time. Again it seems common to induce spawning from hormone injections but natural spawning is possible with environmental manipulation (high speed of running water). Click for more detailed info on breeding programme. 

Tilapia (Oreochromis niloticus)
The fishes’ reproductive behaviour was originally seen as one of its most valuable characteristics, making it unnecessary for small-scale farmers to repeatedly purchase hatchery produced seed, and contributed to its promotion and distribution for rural development purposes throughout the tropics. Quote from
File:Vatch pla nin.jpgTilapia easily breed with out the use of hormone injections. They are maternal mouth brooders that care for their young. This is a very important issue for small scale aquaculture because it means that the subsistence farmers may not need to continually re invest in brood stock. The negative aspect of Tilapia as aquaculture fish is that raised naturally in ponds or paddy fields with mixed sexes they only attain a small size. Fish farming methods have developed the use of hormones (again)to reverse the gender of female fry to turn a batch of Tilapia into a male monosex brood that will grown faster and end up bigger, which makes them more marketable. This is a much more economically viable way to breed large stocks of Tilapia but it is not necessary for a rice paddy field farmer to adopt these methods. I think the breeding method of Tilapia make them a prime candidate for Cambodian subsistence farmers. (Even if they are reported to taste a bit funny sometimes)

Common carp (Cyprinus carpio)
Whilst in the UK the common carp is seen mainly as an angling species across the world it is the number 1 most popular aquaculture fish. With tonnes and tonnes of carp being produced and eaten every day. They are popular in tropical conditions for growing up to the size of 1kg in a single season when in temperate  conditions it could take between 2-4 seasons to reach that weight. The fish can reproduce naturally in ponds and paddy fields with out human intervention but it is more profitable to use hormonal injections.  Thefishsite has this excellent article about all things common carp. This fish is potentially very useful for a small scale aquaculture venture but faces stiff competition in the market place from more large scale intensive farming set ups. 

From my very basic introductory research it seems like Pangasius catfish could be the best cash crop, the silver barb may be the fast grower, the Tilapia may be the easiest to sustain over many years and the common carp is a good all rounder. I think that a good NGO or aid agency project helping rice field paddy farmers branch out into aquaculture could make use of all of these 4 species. Imagining starting them off with some Silver Barb fingerlings so they could quickly start to harvest and eat their own fresh fish this should help encourage them to keep going with the project. Whilst having some Pangasius catfish and common carp growing on to sell at market for some extra cash. Setting them up with some Tilapia to have a constant fish supply with no more start up investment would be an important part of helping the farmer become self sufficient. I believe that Tilapia may be most useful in more remote areas where access to any good quality fingerlings at reasonable prices is most difficult. I think some agencies are already doing some excellent work on this issue and I look forward to reading more in the future. I hope to eat all 4 of these fish when travelling in South East Asia.


Aquaculture seems like a fascinating aspect of food production that could make a massive impact both for individual subsistence farmers and possibly global food supplies (see this video of a suggestion to bring aquaculture into the city life but Urban Aquaculture is another post). Every report I have read (like this report) highlights that for aquaculture to really take off and become sustainable in Cambodia two things need to happen

  • Raise awareness of aquaculture techniques (suitable for the individuals location. 
  • Infrastructure for supplies of seed, fingerlings and feed are improved.
I hope when I get to visit Cambodia i will get to see in practice what all this work is about and see how it is helping people. 

Further reading and key sites 
Cambodian blog about all information on Agriculture sector in Cambodia
Fisheries and Aquaculture Department - Food and Agriculture Organization of the United Nations, serving the global aquaculture industry

WorldFish Centre - Reducing poverty and hunger by improving fisheries and aquaculture
Fish Base - A Global Information System on Fishes


Danish Smith said…
I am very interested in Hydroponics. You somehow have this mini-ecosystem growing food in your house. The plant roots in the water feed the fish, the plants eat the fish poo, you eat the plants AND the fish. Does anyone know of any schools in San Francisco that teach classes about hobby of fish keeping?
Toni McHenry said…
Who was Albert Fish, and what did he do?

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