Atlantic salmon, Pacific salmon and rainbow trout, collectively known as salmonids, are the most farmed carnivorous fish species in the world, mainly because they are prized food fish and relatively easy to culture. Salmon and trout can survive in a variety of environmental conditions, such as water temperatures from 0oC to as high as 28oC for some trout strains. They spawn successfully in water temperatures from 2oC to 15oC, and grow at temperatures from 6oC to 25oC. Depending upon their diet, salmon and trout can have pigmented (red) or non-pigmented (white) flesh. Salmon and trout are sometimes thought of as freshwater fish and other times as marine fish, but they are very adaptable to a variety of saline conditions.