Trout require dO2 of 3ppm to survive. When water reaches a temperature of 75 degrees fahrenheit 3ppm is the maximum dO2 the water can hold with out some form of turbulence to enhance gas exchange (oxygenation). At water temperatures above 75 f with no oxygenation of the water the trout will suffocate. The dO2 super saturation water temperature is 32 f. Water temperature also controls the trout’s metabolism. While very cold water can hold the maximum of dO2 it also slows the trout’s metabolism to the point of suspended animation ( a cryogenic effect ).