Biological control is something that has to be done very carefully. Introducing any species into a different biotope can cause problems if it competes for food with other species, or if it is predatory on other species. There have been several biological disasters where something was introduced to get rid of some kind of parasite, and ended up taking over.
These loaches have a bonus in that they provide food for the farmers, too.
Just remember: Never release fish from your aquarium into a stream, pond or lake.