2. Concrete ponds

Concrete ponds are used for intensive fish farming; concrete walls/banks eliminate erosion due to currents caused by mechanical aeration, waves generated by the wind and fish activity (notably nesting behaviour). This type of pond is more expensive to build and, therefore, should be made profitable by a higher production per volume utilised. Conversely, the firmer walling reduces maintenance and re-building costs that will be necessary after a few years of operation,

This type of pond is smaller than earthen ponds and should not exceed 1,000 m² surface area. The bottom can also be in concrete but for reasons of construction costs, only if the pond size does not exceed 200 m². Brick or stone walls must have strong foundations and, if they are built with bricks or blocks, they must be plastered, in order to avoid the effects of erosion.