Evaluation of the poly- and monoculture production of the common carp Cyprinus carpio L. and the sharptooth catfish Clarias gariepinus (Burchell) in final effluent oxidation pond water of a sewage purification system Evaluation of the poly- and monoculture production of the common carp Cyprinus carpio L. and the sharptooth catfish Clarias gariepinus (Burchell) in final effluent oxidation pond water of a sewage purification system Posted in .