Fish are being used to help eradicate malaria in India with considerable success, according to a report by the BBC.
The work, undertaken by the Indian Research Council, has used small insectivorous fishes such as guppies to help control the Anopheles mosquito population of freshwaters in four Indian states. Their introduction has resulted in a steady drop in the number of malaria cases each year.
While the use of fish does not work in every case, it is both cheaper than chemical methods of attack and the mosquitoes do not become resistant to it.