Grey mullet are grown in earthen ponds all over the world, and can be raised in fresh, brackish, or saltwater. Some farmers raise mullet in a polyculture system with complementary species such as carp, tilapia or milkfish, while others grow mullet as a single species or monoculture. The ponds used to culture grey mullet are first dug or ploughed, then left to dry by the sun, and finally given a layer of manure. The ponds are then filled with a shallow layer of water to establish natural feed (algae). When ready for stocking, the water level is increased and fingerlings are added. Some farmers will continue to add fertilizer throughout the growing cycle to aid productivity, and some will also supply feed beyond what is naturally occuring in the pond. Others prefer to grow mullet without any inputs to the ponds.