I have a BIL that did a stint in the Peace Corps in the Central African Republic.

The project was to use Tilapia to add protein to the diet of subsistence farmers. The Peace Corps helped make shallow ponds suitable for Tilapia that were located between the villages and the crop fields.

The villagers were supposed to throw in some vegetation on their way to the fields, and then again on the way home to feed the Tilapia.

Unfortunately, the projects failed.