Worldwide, about 850,000 tons of rainbow trout (Oncorhynchus mykiss) were produced in 2018 (FAO, 2020). The rainbow trout is one of the most popular and also most produced fish species in Germany. The most important producing countries worldwide include Turkey and Iran (FIZ, 2020). 
Pond systems are particularly suitable for the semi-intensive rearing of trout. For intensive aquaculture, mainly net pens, flow through and recirculating systems are used.

Sources and detailed scientific information on trout can be found at: