Rainbow trout (Salmo gairdneri) were stocked at 3,700, 6,200, and 8,650 fish per hectare on November 16, 1977, in standing-water ponds at Auburn, Alabama. Each treatment was replicated four times. Fish were fed daily with commercial, floating trout feed. Average net production values, in order of increasing stocking rates, were 700, 1,130, and 1,640 kg/hectare at harvest on March 16, 1978. Feed conversion values (weight feed ÷ net production) ranged from 1.15 to 1.27. The winter was cooler than normal and water temperatures never exceeded 19 C (average, 9 C). Feed consumption by rainbow trout is reduced at water temperatures below 10 C. Other water quality variables were within desirable ranges for rainbow trout. Concentrations of dissolved oxygen (DO) at dawn were closely correlated with water temperatures. Nighttime DO budgets for ponds indicated that DO dynamics were dominated by diffusion.