Widowed Esnat Singano, 54, did not know her husband was HIV positive until almost two years after his death in 2000, when she also tested positive for the virus.

After one of her four children also died as a result of the disease, she was left to care for two of her grandchildren and struggled to find the money to send them to primary school. "They needed clothes and food and many other things to be in class; these are the things I could not afford," she told IRIN/PlusNews.

Life has become a little easier for Singano since World Vision, an international relief organisation operating in Malawi, introduced a food security programme in her village in the southeastern district of Zomba two years ago.

"I have been able to grow maize twice a year," she said. "But, more importantly, the introduction of a fish-farming project has changed my life."

The programme funded by the World Bank, which aims to increase the income and nutritional status of households affected by HIV/AIDS, helped Singano to build two fish ponds last year.

"I jumped on the idea when it was told to us by World Vision," she said. "Clubs were formed and many people joined. It is now a year since I started farming fish and so far I have harvested three times; from it I have made 1,200 Malawian kwacha (US$850)."

Besides the income Singano earns from selling her fish, they are also an important source of food for her and her grandchildren.

Timamu Muhajiri, 77, is another beneficiary of the project. After 30 years working a mine in Zimbabwe, in 1991 he returned home with his wife, 10 children and five grandchildren. He said the pension he received from his former employer was a fraction of what he earned from his two fish ponds, which yielded a "harvest" worth about US$550 every three months.

"I think I have been wasting a lot of time and money looking for employment outside the country," Muhajiri said. "What I needed was only the technology to improve my farming."

Over 1,000 households headed by orphans and widows have benefited from the World Vision project, which receives technical support from the WorldFish Centre, a non-profit, international research organisation.

Families with small plots of land were helped to dig small, rain-fed ponds, where they raise tilapia, a common local fish species. There are five species of tilapiine cichlids recorded from Lake Malawi, and other species of the fish occur worldwide.

Although the project implementers pulled out in July 2006, families in the Zomba area, where over 60 percent of the population live in poverty, are now earning an income from their fishponds.

The WorldFish Centre developed the project with mainly the children and elderly in mind, because the ponds require little heavy labour and the fish can be fed with farm and kitchen waste.

"The basic principle of integrated agriculture-aquaculture is to grow fish in water bodies that are closely integrated into a household farm, and intentionally make use of the resource flows of all the diverse activities on a farm, such as livestock, vegetables and crops," said Daniel Jamu, the WorldFish Centre's regional director.

He said fish could provide essential nutrients to the 14 percent of Malawi's population estimated to be living with HIV. The ponds yield about 1,500kg of fish per hectare per year, which often leaves some excess that can be sold to pay for medical care and household needs.

Malawi's expanding population has led to a growing demand for fish, but over-fishing of Lake Malawi and the Shire River has caused a decline in fish stocks and reduced annual per capita fish consumption from 14kg in the 1970s to 4.2kg in 2005.

According to Jamu, the success of the fish-farming project in Zomba has enabled his centre and its partners to expand the initiative to include 26,000 farming households in Malawi and neighbouring Mozambique and Zambia.