Throughout the growing season, from March to October, marked fish usually made a daily trip to the feeding station. In the spring, they did not use the demand feeders until temperatures reached 12 C and they stopped demand feeding in the fall at approximately 22 C. In the spring, intermittent feeding appeared to be primarily temperature related. At cold temperatures fish did not feed daily. After the water had warmed to 22 C fish fed on a daily basis. During summer, low oxygen concentrations often caused fish to adjust or miss their daily feeding period. Feeding was reduced at oxygen values below 5 mg/liter, but fish occasionally fed at values as low as 3 mg/liter.