Credit: Godfrey Byaruhanga (Uganda)
In such breeding system, fish gets conditioned to flowing water and follows the direction opposite to the current. During this period, the broodfish starts to breed. Such fish species include Nile perch, Chinese carps (in particular grass carp).
The oval construction is composed of water outlets with control valves. When the valve is opened, the water under high pressure is pushed through the outlet pipe making anti-clockwise water circulation.