If you blow up the figure at this link, one sees that the 3 statistically equivalent top items in the stomachs of CC are vegetation, fish, and crayfish (in this study).
That's not a good generalization of the study nor a good inference from the chart. There are 5 items averaging around .10 and Then vegetation ~.54, crayfish ~.45, and fish ~.42. Together they should sum to 1.0 (instead > 1.50). Since they don't, there must be further groupings in the data that are not shown in the graph. For example, perhaps of those fish that had fish in their stomachs ... the mean proportion by weight was .42. What this doesn't tell us is what proportion of the entire sample had fish in their stomach. It also doesn't tell us what proportion of the total weight of stomach contents was fish. The proportion of total weight is something their data can provide (though provably not in the graph). Even so, to be representive of the CC population the sampling would have to be consistent in frequency of catfish weights to the frequency of catfish weight in the population. If the sampling method tended to favor collection of older fish, then any generalizations about the population would be highly questionable.
Look guys CC eat fish and are predators. One of the key differences between them and (blues or flathead) is that they are relatively poor predators. It's a good thing they can make use of vegetation, mussels, and insects. Being a relatively poor predator compared to their competitors would really suck if they could not exploit other food.
I have caught a number of CC on small crank baits ... between 15" and 18". I also fish a lot with BG as live bait in the same water. I have never caught one that small using bait 3" to 5". I have caught some dandy >5 lb CC on this size bait however. In the same water ... at the same time ... I will catch the big CC on live bait a few feet from shore obviously hunting for BG and 2 lb CC in deeper water on hotdogs or cut bait. When I have opened them, the smaller fish are packed with filamentous algae. I release the large CC.
