The mysterious fish body part making fishermen filthy rich

Fishermen in Siaya County are cashing in on the sale of Nile perch even as many wonder why there is high demand for the fish swim bladder, popularly known as ‘mondo’. Many fish use swim bladders to help them with quick depth changes. These bladders fill with air to help fish rise or release air so fish can sink, often in conjunction with forward movement.

Some fish, however, don’t have swim bladders.
Nile perch and mudfish are particularly famous for their huge swim bladders, which sometimes can weigh as much as two kilogrammes.