Tank fish ponds. Photo gallery.

Kamuthanga Fish Farm in Machakos is using Recirculating Aquaculture System (RAS) that halves fish maturity period from eight to four months thus enabling the farm meet its market demands besides improving food security.

The technology involves keeping fish in a grower-out chamber, which is basically a tank that has air and water circulating unit with lighting provided by some translucent iron sheets to control temperatures and allow the fish to feed all day and night.

Getting right water parameters which include water pH, temperature, nitrogen and carbon dioxide with good oxygen circulation throughout is all one needs to run a successful aquaculture business,” said the farm’s founder and managing director, Anthony Ndeto.

“With this system in place one is assured of a stress-free environment for the fish, enabling better feeding, thus stimulating growth.”

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According to Ndeto, feeding fish is the way to improve production and the best condition for proper fish feeding is when temperatures are high.

“I used to harvest just a tonne of fish using a 300 square-metre pond but now the farm harvest harvest and sell about 70 tonnes of adult tilapia and thousands of fingerling every year,” he said.

The temperatures are maintained at between 28 and 30 degrees centigrade, and the fingerlings are grouped according to their ages as they become ready for sale at one month.

The farm grows about 40,000 fingerings and sell the rest, mostly to small-scale farmers at an average of Sh10 per fingerling.

They harvest the fish at between four and six months under the technology, while in ponds, it is ready at eight months as they mature faster due to RAS that allow them eat all day all night.

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RAS not only speed fish maturity but also increases fish weight. Fish weighs 400-500 grams at four months under the technology while in ponds the average weight of tilapia fish after a period of one year is 300 grams.

“The reason why there is a big difference is because RAS also ensures the system is clean and the fish has no residues that could have been in feeds,” said Ndeto adding that though the farm is among the 24 listed farms to export fish to EU, the local market is still big enough.

“We are yet to start exporting our fish but for the time being we are still supplying our local consumers who are increasing daily.”

The farm sells a kilo of fish for Sh500.

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It imports starter feeds from Egypt to supplement the ones they make with the help of FoodTechAfrica, a partnership that brings together Dutch and Kenyan companies.

The farm has a hatchery where about 200,000 eggs are hatched monthly.