How to reap handsome returns by keeping tilapia in your backyard

Bonventure Onyango (in a vest) and his friends harvest tilapia from a pond located Ngong in Kajiado County.[Nanjinia Wamuswa, Standard]

Modern fish farming is gaining popularity as a way of increasing income and supplementing the already dwindling supply from Lake Victoria due to pollution, overfishing and weed infestation.

One of the most popular fish species is tilapia. 

A backyard fishpond for tilapia will increase a family’s income because fish is quality food, which is suitable for processing into dried, smoked or salted. Tilapia grows fast and reaches marketable weight of at least 200 grammes in less than six months.

David Karugu has two ponds in Kiambu County and gives insights on what one needs to start a small fish farm.

Selecting land area

While selecting land, keep in mind some necessary facilities which are a must for fish culture. They include a good source of fresh water supply and type of the soil. Karugu pumps water from a nearby river for his fish.

The water must be free from pesticide contamination and pollution, according to Karugu.

Pond Design and Construction

For 200 to 500 fingerlings, one needs at least 100 square metre pond. Karugu started with two ponds with 250 fingerlings in one. The other is a grow-out pond for matured fish.

Pond construction in Kenya costs about Sh150 to Sh500 per square metre of pond depending on the soil type and weather. These rates are from the Ministry of Agriculture. “A well-designed pond, which is dictated by the fish species, ensures good health and maximum production,” says Karugu.

To ensure no fish will escape, fine-meshed wire should screen the drainage area.

Fill the pond with water at an initial depth of five to 10cm after the application of organic fertiliser (preferably chicken manure) for a week. This would allow the growing of algae to serve as natural feed for the fish. Growth can be observed through the greenish coloration of water.


You can get fingerlings from marine shops, other fish farms or at Kenya Marine and Fisheries Research Institute (KMFRI), which has offices countrywide.

Prices range from Sh4 to Sh7 a piece, depending on age and size.

Nathan Irungu’s a teacher by profession feeds his catfish rared in a raised fish pond at Mercy Njeri estate, outskirts of Nakuru town.[Mercy Kahenda]

He advises that farmers should deliver the fingerlings to the pond in oxygenated plastic bags to ensure maximum survival of the fingerlings.

“To assimilate water in plastic bags, open the plastic bags of fingerlings to float within the pond from 30 minutes to one hour. Open the plastic bags in water to allow the fingerlings to swim freely,” advises Karugu.

Gradually remove excess fingerlings after the third month of stocking.


Feed the tilapias twice daily (morning and afternoon). Supplement feeds with fine rice bran, bread crumbs and earthworms

Karugu’s largest expense item is feed, which goes for Sh3,000 for a 20-kilogramme bag, followed by the cost of pumping river water into the ponds. His fish consumes about 20 kilogrammes of feed a week.


Karugu introduced catfish into the pond to control the population of small fishes for at least three months before harvest. After four to six months, tilapias weigh 200 to 400 grammes and are ready for harvest.

“Drain the pond totally and allow fish to accommodate the lowest portion in the drainage area for easy harvesting. After harvesting stock the pond again.” 


Karugu sells mature fish at Sh400 a kilo, harvesting an average of 80kg per pond (about 200 mature fish). From one pond, this translates to Sh32,000.

His market is mainly online, referrals and nearby restaurants.

Other care and management

Do all tasks timely and accurately. If necessary, change the water of the pond. Examine the quality of water and soil on regular basis.

Use proper medicines for the fish to keep them healthy and diseases-free. Prevent the entrance of predators like snakes and frog. Use a net while filling the pond with water.

Jennifer Anyango