I mix food all the time but don't have CC. Take a look at this SRAC fact sheet on CC feeding. I don't think a mixed diet would hurt the CC.

Channel Catfish Production

http://srac.tamu.edu/tmppdfs/127565-187f...65749bb746940e6


Past studies have indicated that
optimal protein levels for channel
catfish diets are between 25 and 45
percent.

A study at Auburn University
measured the effects of feeding
commercial-type diets containing
24, 28, 32, 36 or 40 percent protein
to third-year catfish in ponds. Fish
were stocked at 1,977 per acre and
went from an average size of 1.3
pounds to an average of 3.6
pounds in 141 days. They were fed
to satiation once daily.